Routing from 2 WAN to same LAN
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I'm using a Linux based router appliance (named Zeroshell), but it should be a question related to generic Linux routing.
The router computer has 4 NICs, named ETH0 to ETH3.
- ETH0 is on the actual LAN (subnet 192.168.241.0/24) IP 192.168.241.254
- ETH1 is on a WAN connection router (subnet 192.168.1.0/24) IP 192.168.1.1, GW 192.168.1.254
- ETH2 is on a another WAN connection router (subnet 192.168.2.0/24) IP 192.168.2.1, GW 192.168.2.254
- ETH3 is on another LAN dedicated for guests (subnet 192.168.230.0/24) IP 192.168.230.254
The default gateway on the router is set to 192.168.2.254 so all outgoing traffic uses the second WAN connection (optic fiber), and NAT is enabled on both ETH1 and ETH2.
On first WAN router, 192.168.1.1 is set as the DMZ.
On second WAN router, 192.168.2.1 is set as the DMZ.
I've set some port forwarding on port 80 on both ETH1 and ETH2 to a computer lying in the ETH0 subnet.
When connecting to the second WAN's public IP with a browser, I get the website hosted on the internal computer.
When connecting to the first WAN's public IP with a browser, connection stays stuck.
I'm pretty sure this has to deal with the default gateway set to the second WAN's router making all traffic go to him, even if it originated from the first WAN router.
So my question is : HOW should I configure the routing tables on my router so that it can handle incoming connections from both WANs, forward them to the relevant LAN computer and route answers to the proper WAN ?
EDIT:
Adding routing tables from the Webserver :
root@webserver:/# ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 00:15:5d:f1:03:10 brd ff:ff:ff:ff:ff:ff
inet 192.168.241.23/24 brd 192.168.241.255 scope global eth0
valid_lft forever preferred_lft forever
root@webserver:/# ip route show
default via 192.168.241.254 dev eth0
10.8.0.0/24 via 192.168.241.21 dev eth0
192.168.240.0/24 via 192.168.241.21 dev eth0
192.168.241.0/24 dev eth0 proto kernel scope link src 192.168.241.23
Adding routing tables from the Router :
root@rtr ~> ip addr show
1: lo: <LOOPBACK,UP,10000> mtu 65536 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: sit0@NONE: <NOARP> mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
3: ETH00: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc mq qlen 1000
link/ether 00:15:5d:f1:05:08 brd ff:ff:ff:ff:ff:ff
inet 192.168.230.254/24 brd 192.168.230.255 scope global ETH00:00
valid_lft forever preferred_lft forever
inet6 fe80::215:5dff:fef1:508/64 scope link
valid_lft forever preferred_lft forever
4: ETH01: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc mq qlen 1000
link/ether 00:15:5d:f1:05:09 brd ff:ff:ff:ff:ff:ff
inet 192.168.2.1/24 brd 192.168.2.255 scope global ETH01:00
valid_lft forever preferred_lft forever
inet6 2a01:e35:2e74:9560:215:5dff:fef1:509/64 scope global dynamic
valid_lft 86156sec preferred_lft 86156sec
inet6 fe80::215:5dff:fef1:509/64 scope link
valid_lft forever preferred_lft forever
5: ETH02: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc mq qlen 1000
link/ether 00:15:5d:f1:05:0b brd ff:ff:ff:ff:ff:ff
inet 192.168.1.1/24 brd 192.168.1.255 scope global ETH02:00
valid_lft forever preferred_lft forever
inet6 fe80::215:5dff:fef1:50b/64 scope link
valid_lft forever preferred_lft forever
6: ETH03: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc mq qlen 1000
link/ether 00:15:5d:f1:05:0c brd ff:ff:ff:ff:ff:ff
inet 192.168.241.254/24 brd 192.168.241.255 scope global ETH03:00
valid_lft forever preferred_lft forever
inet6 fe80::215:5dff:fef1:50c/64 scope link
valid_lft forever preferred_lft forever
7: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noqueue
link/ether 9e:3d:6a:0e:65:39 brd ff:ff:ff:ff:ff:ff
inet 192.168.141.142/24 brd 192.168.141.255 scope global dummy0
valid_lft forever preferred_lft forever
8: dummy1: <BROADCAST,NOARP,UP,10000> mtu 1500 qdisc noqueue
link/ether ee:6e:6f:33:32:34 brd ff:ff:ff:ff:ff:ff
inet 192.168.142.142/32 brd 192.168.142.255 scope global dummy1
valid_lft forever preferred_lft forever
inet6 fe80::ec6e:6fff:fe33:3234/64 scope link
valid_lft forever preferred_lft forever
9: DEFAULTBR: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
link/ether 0a:61:ef:f2:09:80 brd ff:ff:ff:ff:ff:ff
10: VPN99: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 10 0
link/ether 1a:e8:0e:ee:78:aa brd ff:ff:ff:ff:ff:ff
inet 192.168.250.254/24 brd 192.168.250.255 scope global VPN99:00
valid_lft forever preferred_lft forever
11: bond0: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 8e:65:6c:3d:76:e5 brd ff:ff:ff:ff:ff:ff
12: bond1: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 1e:34:34:54:8d:48 brd ff:ff:ff:ff:ff:ff
13: bond2: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 5a:bc:4c:86:83:dc brd ff:ff:ff:ff:ff:ff
14: bond3: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 6e:81:53:3e:0a:ff brd ff:ff:ff:ff:ff:ff
15: bond4: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 6a:35:c8:45:d1:ff brd ff:ff:ff:ff:ff:ff
16: bond5: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether ca:5d:10:21:02:30 brd ff:ff:ff:ff:ff:ff
17: bond6: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 82:60:85:97:d4:90 brd ff:ff:ff:ff:ff:ff
18: bond7: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether b6:fc:c9:a5:06:73 brd ff:ff:ff:ff:ff:ff
19: bond8: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether ce:75:5d:e5:7d:69 brd ff:ff:ff:ff:ff:ff
20: bond9: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 2e:ef:1e:89:26:1b brd ff:ff:ff:ff:ff:ff
root@rtr ~> ip route show
default via 192.168.1.254 dev ETH02
192.168.1.0/24 dev ETH02 proto kernel scope link src 192.168.1.1
192.168.2.0/24 dev ETH01 proto kernel scope link src 192.168.2.1
192.168.230.0/24 dev ETH00 proto kernel scope link src 192.168.230.254
192.168.240.0/24 via 192.168.241.21 dev ETH03
192.168.241.0/24 dev ETH03 proto kernel scope link src 192.168.241.254
192.168.250.0/24 dev VPN99 proto kernel scope link src 192.168.250.254
linux iptables firewall routing
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up vote
2
down vote
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I'm using a Linux based router appliance (named Zeroshell), but it should be a question related to generic Linux routing.
The router computer has 4 NICs, named ETH0 to ETH3.
- ETH0 is on the actual LAN (subnet 192.168.241.0/24) IP 192.168.241.254
- ETH1 is on a WAN connection router (subnet 192.168.1.0/24) IP 192.168.1.1, GW 192.168.1.254
- ETH2 is on a another WAN connection router (subnet 192.168.2.0/24) IP 192.168.2.1, GW 192.168.2.254
- ETH3 is on another LAN dedicated for guests (subnet 192.168.230.0/24) IP 192.168.230.254
The default gateway on the router is set to 192.168.2.254 so all outgoing traffic uses the second WAN connection (optic fiber), and NAT is enabled on both ETH1 and ETH2.
On first WAN router, 192.168.1.1 is set as the DMZ.
On second WAN router, 192.168.2.1 is set as the DMZ.
I've set some port forwarding on port 80 on both ETH1 and ETH2 to a computer lying in the ETH0 subnet.
When connecting to the second WAN's public IP with a browser, I get the website hosted on the internal computer.
When connecting to the first WAN's public IP with a browser, connection stays stuck.
I'm pretty sure this has to deal with the default gateway set to the second WAN's router making all traffic go to him, even if it originated from the first WAN router.
So my question is : HOW should I configure the routing tables on my router so that it can handle incoming connections from both WANs, forward them to the relevant LAN computer and route answers to the proper WAN ?
EDIT:
Adding routing tables from the Webserver :
root@webserver:/# ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 00:15:5d:f1:03:10 brd ff:ff:ff:ff:ff:ff
inet 192.168.241.23/24 brd 192.168.241.255 scope global eth0
valid_lft forever preferred_lft forever
root@webserver:/# ip route show
default via 192.168.241.254 dev eth0
10.8.0.0/24 via 192.168.241.21 dev eth0
192.168.240.0/24 via 192.168.241.21 dev eth0
192.168.241.0/24 dev eth0 proto kernel scope link src 192.168.241.23
Adding routing tables from the Router :
root@rtr ~> ip addr show
1: lo: <LOOPBACK,UP,10000> mtu 65536 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: sit0@NONE: <NOARP> mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
3: ETH00: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc mq qlen 1000
link/ether 00:15:5d:f1:05:08 brd ff:ff:ff:ff:ff:ff
inet 192.168.230.254/24 brd 192.168.230.255 scope global ETH00:00
valid_lft forever preferred_lft forever
inet6 fe80::215:5dff:fef1:508/64 scope link
valid_lft forever preferred_lft forever
4: ETH01: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc mq qlen 1000
link/ether 00:15:5d:f1:05:09 brd ff:ff:ff:ff:ff:ff
inet 192.168.2.1/24 brd 192.168.2.255 scope global ETH01:00
valid_lft forever preferred_lft forever
inet6 2a01:e35:2e74:9560:215:5dff:fef1:509/64 scope global dynamic
valid_lft 86156sec preferred_lft 86156sec
inet6 fe80::215:5dff:fef1:509/64 scope link
valid_lft forever preferred_lft forever
5: ETH02: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc mq qlen 1000
link/ether 00:15:5d:f1:05:0b brd ff:ff:ff:ff:ff:ff
inet 192.168.1.1/24 brd 192.168.1.255 scope global ETH02:00
valid_lft forever preferred_lft forever
inet6 fe80::215:5dff:fef1:50b/64 scope link
valid_lft forever preferred_lft forever
6: ETH03: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc mq qlen 1000
link/ether 00:15:5d:f1:05:0c brd ff:ff:ff:ff:ff:ff
inet 192.168.241.254/24 brd 192.168.241.255 scope global ETH03:00
valid_lft forever preferred_lft forever
inet6 fe80::215:5dff:fef1:50c/64 scope link
valid_lft forever preferred_lft forever
7: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noqueue
link/ether 9e:3d:6a:0e:65:39 brd ff:ff:ff:ff:ff:ff
inet 192.168.141.142/24 brd 192.168.141.255 scope global dummy0
valid_lft forever preferred_lft forever
8: dummy1: <BROADCAST,NOARP,UP,10000> mtu 1500 qdisc noqueue
link/ether ee:6e:6f:33:32:34 brd ff:ff:ff:ff:ff:ff
inet 192.168.142.142/32 brd 192.168.142.255 scope global dummy1
valid_lft forever preferred_lft forever
inet6 fe80::ec6e:6fff:fe33:3234/64 scope link
valid_lft forever preferred_lft forever
9: DEFAULTBR: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
link/ether 0a:61:ef:f2:09:80 brd ff:ff:ff:ff:ff:ff
10: VPN99: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 10 0
link/ether 1a:e8:0e:ee:78:aa brd ff:ff:ff:ff:ff:ff
inet 192.168.250.254/24 brd 192.168.250.255 scope global VPN99:00
valid_lft forever preferred_lft forever
11: bond0: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 8e:65:6c:3d:76:e5 brd ff:ff:ff:ff:ff:ff
12: bond1: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 1e:34:34:54:8d:48 brd ff:ff:ff:ff:ff:ff
13: bond2: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 5a:bc:4c:86:83:dc brd ff:ff:ff:ff:ff:ff
14: bond3: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 6e:81:53:3e:0a:ff brd ff:ff:ff:ff:ff:ff
15: bond4: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 6a:35:c8:45:d1:ff brd ff:ff:ff:ff:ff:ff
16: bond5: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether ca:5d:10:21:02:30 brd ff:ff:ff:ff:ff:ff
17: bond6: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 82:60:85:97:d4:90 brd ff:ff:ff:ff:ff:ff
18: bond7: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether b6:fc:c9:a5:06:73 brd ff:ff:ff:ff:ff:ff
19: bond8: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether ce:75:5d:e5:7d:69 brd ff:ff:ff:ff:ff:ff
20: bond9: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 2e:ef:1e:89:26:1b brd ff:ff:ff:ff:ff:ff
root@rtr ~> ip route show
default via 192.168.1.254 dev ETH02
192.168.1.0/24 dev ETH02 proto kernel scope link src 192.168.1.1
192.168.2.0/24 dev ETH01 proto kernel scope link src 192.168.2.1
192.168.230.0/24 dev ETH00 proto kernel scope link src 192.168.230.254
192.168.240.0/24 via 192.168.241.21 dev ETH03
192.168.241.0/24 dev ETH03 proto kernel scope link src 192.168.241.254
192.168.250.0/24 dev VPN99 proto kernel scope link src 192.168.250.254
linux iptables firewall routing
Please show us the routing tables of both router and web server. Use the commandip addr show; ip route show
on both servers
â andcoz
Jan 23 at 10:17
Is the router set up to NAT between the LAN and WANs?
â CyberJacob
Jan 23 at 10:24
Added the requested routing tables and yes, NAT is enabled and working fine.
â Sierramike
Jan 23 at 14:06
add a comment |Â
up vote
2
down vote
favorite
up vote
2
down vote
favorite
I'm using a Linux based router appliance (named Zeroshell), but it should be a question related to generic Linux routing.
The router computer has 4 NICs, named ETH0 to ETH3.
- ETH0 is on the actual LAN (subnet 192.168.241.0/24) IP 192.168.241.254
- ETH1 is on a WAN connection router (subnet 192.168.1.0/24) IP 192.168.1.1, GW 192.168.1.254
- ETH2 is on a another WAN connection router (subnet 192.168.2.0/24) IP 192.168.2.1, GW 192.168.2.254
- ETH3 is on another LAN dedicated for guests (subnet 192.168.230.0/24) IP 192.168.230.254
The default gateway on the router is set to 192.168.2.254 so all outgoing traffic uses the second WAN connection (optic fiber), and NAT is enabled on both ETH1 and ETH2.
On first WAN router, 192.168.1.1 is set as the DMZ.
On second WAN router, 192.168.2.1 is set as the DMZ.
I've set some port forwarding on port 80 on both ETH1 and ETH2 to a computer lying in the ETH0 subnet.
When connecting to the second WAN's public IP with a browser, I get the website hosted on the internal computer.
When connecting to the first WAN's public IP with a browser, connection stays stuck.
I'm pretty sure this has to deal with the default gateway set to the second WAN's router making all traffic go to him, even if it originated from the first WAN router.
So my question is : HOW should I configure the routing tables on my router so that it can handle incoming connections from both WANs, forward them to the relevant LAN computer and route answers to the proper WAN ?
EDIT:
Adding routing tables from the Webserver :
root@webserver:/# ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 00:15:5d:f1:03:10 brd ff:ff:ff:ff:ff:ff
inet 192.168.241.23/24 brd 192.168.241.255 scope global eth0
valid_lft forever preferred_lft forever
root@webserver:/# ip route show
default via 192.168.241.254 dev eth0
10.8.0.0/24 via 192.168.241.21 dev eth0
192.168.240.0/24 via 192.168.241.21 dev eth0
192.168.241.0/24 dev eth0 proto kernel scope link src 192.168.241.23
Adding routing tables from the Router :
root@rtr ~> ip addr show
1: lo: <LOOPBACK,UP,10000> mtu 65536 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: sit0@NONE: <NOARP> mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
3: ETH00: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc mq qlen 1000
link/ether 00:15:5d:f1:05:08 brd ff:ff:ff:ff:ff:ff
inet 192.168.230.254/24 brd 192.168.230.255 scope global ETH00:00
valid_lft forever preferred_lft forever
inet6 fe80::215:5dff:fef1:508/64 scope link
valid_lft forever preferred_lft forever
4: ETH01: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc mq qlen 1000
link/ether 00:15:5d:f1:05:09 brd ff:ff:ff:ff:ff:ff
inet 192.168.2.1/24 brd 192.168.2.255 scope global ETH01:00
valid_lft forever preferred_lft forever
inet6 2a01:e35:2e74:9560:215:5dff:fef1:509/64 scope global dynamic
valid_lft 86156sec preferred_lft 86156sec
inet6 fe80::215:5dff:fef1:509/64 scope link
valid_lft forever preferred_lft forever
5: ETH02: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc mq qlen 1000
link/ether 00:15:5d:f1:05:0b brd ff:ff:ff:ff:ff:ff
inet 192.168.1.1/24 brd 192.168.1.255 scope global ETH02:00
valid_lft forever preferred_lft forever
inet6 fe80::215:5dff:fef1:50b/64 scope link
valid_lft forever preferred_lft forever
6: ETH03: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc mq qlen 1000
link/ether 00:15:5d:f1:05:0c brd ff:ff:ff:ff:ff:ff
inet 192.168.241.254/24 brd 192.168.241.255 scope global ETH03:00
valid_lft forever preferred_lft forever
inet6 fe80::215:5dff:fef1:50c/64 scope link
valid_lft forever preferred_lft forever
7: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noqueue
link/ether 9e:3d:6a:0e:65:39 brd ff:ff:ff:ff:ff:ff
inet 192.168.141.142/24 brd 192.168.141.255 scope global dummy0
valid_lft forever preferred_lft forever
8: dummy1: <BROADCAST,NOARP,UP,10000> mtu 1500 qdisc noqueue
link/ether ee:6e:6f:33:32:34 brd ff:ff:ff:ff:ff:ff
inet 192.168.142.142/32 brd 192.168.142.255 scope global dummy1
valid_lft forever preferred_lft forever
inet6 fe80::ec6e:6fff:fe33:3234/64 scope link
valid_lft forever preferred_lft forever
9: DEFAULTBR: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
link/ether 0a:61:ef:f2:09:80 brd ff:ff:ff:ff:ff:ff
10: VPN99: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 10 0
link/ether 1a:e8:0e:ee:78:aa brd ff:ff:ff:ff:ff:ff
inet 192.168.250.254/24 brd 192.168.250.255 scope global VPN99:00
valid_lft forever preferred_lft forever
11: bond0: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 8e:65:6c:3d:76:e5 brd ff:ff:ff:ff:ff:ff
12: bond1: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 1e:34:34:54:8d:48 brd ff:ff:ff:ff:ff:ff
13: bond2: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 5a:bc:4c:86:83:dc brd ff:ff:ff:ff:ff:ff
14: bond3: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 6e:81:53:3e:0a:ff brd ff:ff:ff:ff:ff:ff
15: bond4: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 6a:35:c8:45:d1:ff brd ff:ff:ff:ff:ff:ff
16: bond5: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether ca:5d:10:21:02:30 brd ff:ff:ff:ff:ff:ff
17: bond6: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 82:60:85:97:d4:90 brd ff:ff:ff:ff:ff:ff
18: bond7: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether b6:fc:c9:a5:06:73 brd ff:ff:ff:ff:ff:ff
19: bond8: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether ce:75:5d:e5:7d:69 brd ff:ff:ff:ff:ff:ff
20: bond9: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 2e:ef:1e:89:26:1b brd ff:ff:ff:ff:ff:ff
root@rtr ~> ip route show
default via 192.168.1.254 dev ETH02
192.168.1.0/24 dev ETH02 proto kernel scope link src 192.168.1.1
192.168.2.0/24 dev ETH01 proto kernel scope link src 192.168.2.1
192.168.230.0/24 dev ETH00 proto kernel scope link src 192.168.230.254
192.168.240.0/24 via 192.168.241.21 dev ETH03
192.168.241.0/24 dev ETH03 proto kernel scope link src 192.168.241.254
192.168.250.0/24 dev VPN99 proto kernel scope link src 192.168.250.254
linux iptables firewall routing
I'm using a Linux based router appliance (named Zeroshell), but it should be a question related to generic Linux routing.
The router computer has 4 NICs, named ETH0 to ETH3.
- ETH0 is on the actual LAN (subnet 192.168.241.0/24) IP 192.168.241.254
- ETH1 is on a WAN connection router (subnet 192.168.1.0/24) IP 192.168.1.1, GW 192.168.1.254
- ETH2 is on a another WAN connection router (subnet 192.168.2.0/24) IP 192.168.2.1, GW 192.168.2.254
- ETH3 is on another LAN dedicated for guests (subnet 192.168.230.0/24) IP 192.168.230.254
The default gateway on the router is set to 192.168.2.254 so all outgoing traffic uses the second WAN connection (optic fiber), and NAT is enabled on both ETH1 and ETH2.
On first WAN router, 192.168.1.1 is set as the DMZ.
On second WAN router, 192.168.2.1 is set as the DMZ.
I've set some port forwarding on port 80 on both ETH1 and ETH2 to a computer lying in the ETH0 subnet.
When connecting to the second WAN's public IP with a browser, I get the website hosted on the internal computer.
When connecting to the first WAN's public IP with a browser, connection stays stuck.
I'm pretty sure this has to deal with the default gateway set to the second WAN's router making all traffic go to him, even if it originated from the first WAN router.
So my question is : HOW should I configure the routing tables on my router so that it can handle incoming connections from both WANs, forward them to the relevant LAN computer and route answers to the proper WAN ?
EDIT:
Adding routing tables from the Webserver :
root@webserver:/# ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 00:15:5d:f1:03:10 brd ff:ff:ff:ff:ff:ff
inet 192.168.241.23/24 brd 192.168.241.255 scope global eth0
valid_lft forever preferred_lft forever
root@webserver:/# ip route show
default via 192.168.241.254 dev eth0
10.8.0.0/24 via 192.168.241.21 dev eth0
192.168.240.0/24 via 192.168.241.21 dev eth0
192.168.241.0/24 dev eth0 proto kernel scope link src 192.168.241.23
Adding routing tables from the Router :
root@rtr ~> ip addr show
1: lo: <LOOPBACK,UP,10000> mtu 65536 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: sit0@NONE: <NOARP> mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
3: ETH00: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc mq qlen 1000
link/ether 00:15:5d:f1:05:08 brd ff:ff:ff:ff:ff:ff
inet 192.168.230.254/24 brd 192.168.230.255 scope global ETH00:00
valid_lft forever preferred_lft forever
inet6 fe80::215:5dff:fef1:508/64 scope link
valid_lft forever preferred_lft forever
4: ETH01: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc mq qlen 1000
link/ether 00:15:5d:f1:05:09 brd ff:ff:ff:ff:ff:ff
inet 192.168.2.1/24 brd 192.168.2.255 scope global ETH01:00
valid_lft forever preferred_lft forever
inet6 2a01:e35:2e74:9560:215:5dff:fef1:509/64 scope global dynamic
valid_lft 86156sec preferred_lft 86156sec
inet6 fe80::215:5dff:fef1:509/64 scope link
valid_lft forever preferred_lft forever
5: ETH02: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc mq qlen 1000
link/ether 00:15:5d:f1:05:0b brd ff:ff:ff:ff:ff:ff
inet 192.168.1.1/24 brd 192.168.1.255 scope global ETH02:00
valid_lft forever preferred_lft forever
inet6 fe80::215:5dff:fef1:50b/64 scope link
valid_lft forever preferred_lft forever
6: ETH03: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc mq qlen 1000
link/ether 00:15:5d:f1:05:0c brd ff:ff:ff:ff:ff:ff
inet 192.168.241.254/24 brd 192.168.241.255 scope global ETH03:00
valid_lft forever preferred_lft forever
inet6 fe80::215:5dff:fef1:50c/64 scope link
valid_lft forever preferred_lft forever
7: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noqueue
link/ether 9e:3d:6a:0e:65:39 brd ff:ff:ff:ff:ff:ff
inet 192.168.141.142/24 brd 192.168.141.255 scope global dummy0
valid_lft forever preferred_lft forever
8: dummy1: <BROADCAST,NOARP,UP,10000> mtu 1500 qdisc noqueue
link/ether ee:6e:6f:33:32:34 brd ff:ff:ff:ff:ff:ff
inet 192.168.142.142/32 brd 192.168.142.255 scope global dummy1
valid_lft forever preferred_lft forever
inet6 fe80::ec6e:6fff:fe33:3234/64 scope link
valid_lft forever preferred_lft forever
9: DEFAULTBR: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
link/ether 0a:61:ef:f2:09:80 brd ff:ff:ff:ff:ff:ff
10: VPN99: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 10 0
link/ether 1a:e8:0e:ee:78:aa brd ff:ff:ff:ff:ff:ff
inet 192.168.250.254/24 brd 192.168.250.255 scope global VPN99:00
valid_lft forever preferred_lft forever
11: bond0: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 8e:65:6c:3d:76:e5 brd ff:ff:ff:ff:ff:ff
12: bond1: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 1e:34:34:54:8d:48 brd ff:ff:ff:ff:ff:ff
13: bond2: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 5a:bc:4c:86:83:dc brd ff:ff:ff:ff:ff:ff
14: bond3: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 6e:81:53:3e:0a:ff brd ff:ff:ff:ff:ff:ff
15: bond4: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 6a:35:c8:45:d1:ff brd ff:ff:ff:ff:ff:ff
16: bond5: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether ca:5d:10:21:02:30 brd ff:ff:ff:ff:ff:ff
17: bond6: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 82:60:85:97:d4:90 brd ff:ff:ff:ff:ff:ff
18: bond7: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether b6:fc:c9:a5:06:73 brd ff:ff:ff:ff:ff:ff
19: bond8: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether ce:75:5d:e5:7d:69 brd ff:ff:ff:ff:ff:ff
20: bond9: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop
link/ether 2e:ef:1e:89:26:1b brd ff:ff:ff:ff:ff:ff
root@rtr ~> ip route show
default via 192.168.1.254 dev ETH02
192.168.1.0/24 dev ETH02 proto kernel scope link src 192.168.1.1
192.168.2.0/24 dev ETH01 proto kernel scope link src 192.168.2.1
192.168.230.0/24 dev ETH00 proto kernel scope link src 192.168.230.254
192.168.240.0/24 via 192.168.241.21 dev ETH03
192.168.241.0/24 dev ETH03 proto kernel scope link src 192.168.241.254
192.168.250.0/24 dev VPN99 proto kernel scope link src 192.168.250.254
linux iptables firewall routing
edited Jan 23 at 14:06
asked Jan 23 at 10:02
Sierramike
112
112
Please show us the routing tables of both router and web server. Use the commandip addr show; ip route show
on both servers
â andcoz
Jan 23 at 10:17
Is the router set up to NAT between the LAN and WANs?
â CyberJacob
Jan 23 at 10:24
Added the requested routing tables and yes, NAT is enabled and working fine.
â Sierramike
Jan 23 at 14:06
add a comment |Â
Please show us the routing tables of both router and web server. Use the commandip addr show; ip route show
on both servers
â andcoz
Jan 23 at 10:17
Is the router set up to NAT between the LAN and WANs?
â CyberJacob
Jan 23 at 10:24
Added the requested routing tables and yes, NAT is enabled and working fine.
â Sierramike
Jan 23 at 14:06
Please show us the routing tables of both router and web server. Use the command
ip addr show; ip route show
on both serversâ andcoz
Jan 23 at 10:17
Please show us the routing tables of both router and web server. Use the command
ip addr show; ip route show
on both serversâ andcoz
Jan 23 at 10:17
Is the router set up to NAT between the LAN and WANs?
â CyberJacob
Jan 23 at 10:24
Is the router set up to NAT between the LAN and WANs?
â CyberJacob
Jan 23 at 10:24
Added the requested routing tables and yes, NAT is enabled and working fine.
â Sierramike
Jan 23 at 14:06
Added the requested routing tables and yes, NAT is enabled and working fine.
â Sierramike
Jan 23 at 14:06
add a comment |Â
1 Answer
1
active
oldest
votes
up vote
2
down vote
The problem with such a dual-homed setup is that the return packets originating from the webserver on the ETH0 network follow the default gateway, which is only correct for connections coming in through that interface. I've run into this myself.
The solution I use is to add an extra IP address to the webserver on the ETH0 network (I'm assuming 192.168.241.24), and use that as the DNAT target for connections coming in through the second WAN interface. Then add a routing rule that the second IP address gets routed out through the second WAN interface.
You need to understand a little bit about Linux policy based routing. Do ip rule show
:
0: from all lookup local
32766: from all lookup main
32767: from all lookup default
When you do ip route show
you show the "main" table as default. You can show one of the other tables by adding table $name
, e.g.:
$ ip route show table local
broadcast 127.0.0.0 dev lo proto kernel scope link src 127.0.0.1
local 127.0.0.0/8 dev lo proto kernel scope host src 127.0.0.1
local 127.0.0.1 dev lo proto kernel scope host src 127.0.0.1
broadcast 127.255.255.255 dev lo proto kernel scope link src 127.0.0.1
broadcast 192.168.0.0 dev eth0 proto kernel scope link src 192.168.1.27
local 192.168.1.27 dev eth0 proto kernel scope host src 192.168.1.27
broadcast 192.168.1.255 dev eth0 proto kernel scope link src 192.168.1.27
You can add your own tables; edit /etc/iproute2/rt_tables
and add two lines:
11 WAN1
12 WAN2
Now you can add the default routes over ETH01 and ETH02 to the respective tables:
# ip route add default via 192.168.2.254 table WAN1
# ip route add default via 192.168.1.254 table WAN2
(You first describe ETH01 as having 192.168.1.254 as gateway and ETH02 and having 192.168.2.254 but then your ip route show
output disagrees, so I'm going with the latter... aside from the ETH1 / ETH01 difference.)
Now you need to add a rule to use the WAN1 table for traffic coming in from the second webserver IP address:
# ip rule add from 192.168.241.24 lookup WAN1 prio 1000
Now, when traffic comes in from ETH01 and gets sent via DNAT to the second IP address of the webserver, the webserver will return packets from that address and the rule will match that address and send return traffic via ETH01.
You don't really need the WAN2 table in this scenario, however if the router system itself needs to be accessible from both WAN interfaces, or if you want to be able to choose what WAN interface for whatever then it's useful to have it.
The issue technically isn't that they go out via the default gateway, but that NAT changes their source IP to that of the default gateway's interface. This is different from the destination IP that the connection was originally established on, and thus is not recognised as the same connection by the remote computer.
â CyberJacob
Jan 23 at 16:08
Some generic (but a bit outdated) infos there: lartc.org/howto/lartc.rpdb.multiple-links.html @wurtel I think you wrotedev ETH01
when you wanted to writetable ETH01
. I'd rather avoid naming the table with the name of the interface, it might confuse (I usually don't bother to name them, I just use the numbers)
â A.B
Jan 23 at 21:18
@CyberJacob there's an RFC (I can't find which right now) that says that an internet connection provider should not accept packets from their clients with source addresses that do not originate from within their address space, to combat spoofing of such addresses, so even if the NAT would set the source IP to the correct one, if the packet goes out through the wrong interface, it probably won't arrive at the destination anyway.
â wurtel
Jan 24 at 7:01
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
2
down vote
The problem with such a dual-homed setup is that the return packets originating from the webserver on the ETH0 network follow the default gateway, which is only correct for connections coming in through that interface. I've run into this myself.
The solution I use is to add an extra IP address to the webserver on the ETH0 network (I'm assuming 192.168.241.24), and use that as the DNAT target for connections coming in through the second WAN interface. Then add a routing rule that the second IP address gets routed out through the second WAN interface.
You need to understand a little bit about Linux policy based routing. Do ip rule show
:
0: from all lookup local
32766: from all lookup main
32767: from all lookup default
When you do ip route show
you show the "main" table as default. You can show one of the other tables by adding table $name
, e.g.:
$ ip route show table local
broadcast 127.0.0.0 dev lo proto kernel scope link src 127.0.0.1
local 127.0.0.0/8 dev lo proto kernel scope host src 127.0.0.1
local 127.0.0.1 dev lo proto kernel scope host src 127.0.0.1
broadcast 127.255.255.255 dev lo proto kernel scope link src 127.0.0.1
broadcast 192.168.0.0 dev eth0 proto kernel scope link src 192.168.1.27
local 192.168.1.27 dev eth0 proto kernel scope host src 192.168.1.27
broadcast 192.168.1.255 dev eth0 proto kernel scope link src 192.168.1.27
You can add your own tables; edit /etc/iproute2/rt_tables
and add two lines:
11 WAN1
12 WAN2
Now you can add the default routes over ETH01 and ETH02 to the respective tables:
# ip route add default via 192.168.2.254 table WAN1
# ip route add default via 192.168.1.254 table WAN2
(You first describe ETH01 as having 192.168.1.254 as gateway and ETH02 and having 192.168.2.254 but then your ip route show
output disagrees, so I'm going with the latter... aside from the ETH1 / ETH01 difference.)
Now you need to add a rule to use the WAN1 table for traffic coming in from the second webserver IP address:
# ip rule add from 192.168.241.24 lookup WAN1 prio 1000
Now, when traffic comes in from ETH01 and gets sent via DNAT to the second IP address of the webserver, the webserver will return packets from that address and the rule will match that address and send return traffic via ETH01.
You don't really need the WAN2 table in this scenario, however if the router system itself needs to be accessible from both WAN interfaces, or if you want to be able to choose what WAN interface for whatever then it's useful to have it.
The issue technically isn't that they go out via the default gateway, but that NAT changes their source IP to that of the default gateway's interface. This is different from the destination IP that the connection was originally established on, and thus is not recognised as the same connection by the remote computer.
â CyberJacob
Jan 23 at 16:08
Some generic (but a bit outdated) infos there: lartc.org/howto/lartc.rpdb.multiple-links.html @wurtel I think you wrotedev ETH01
when you wanted to writetable ETH01
. I'd rather avoid naming the table with the name of the interface, it might confuse (I usually don't bother to name them, I just use the numbers)
â A.B
Jan 23 at 21:18
@CyberJacob there's an RFC (I can't find which right now) that says that an internet connection provider should not accept packets from their clients with source addresses that do not originate from within their address space, to combat spoofing of such addresses, so even if the NAT would set the source IP to the correct one, if the packet goes out through the wrong interface, it probably won't arrive at the destination anyway.
â wurtel
Jan 24 at 7:01
add a comment |Â
up vote
2
down vote
The problem with such a dual-homed setup is that the return packets originating from the webserver on the ETH0 network follow the default gateway, which is only correct for connections coming in through that interface. I've run into this myself.
The solution I use is to add an extra IP address to the webserver on the ETH0 network (I'm assuming 192.168.241.24), and use that as the DNAT target for connections coming in through the second WAN interface. Then add a routing rule that the second IP address gets routed out through the second WAN interface.
You need to understand a little bit about Linux policy based routing. Do ip rule show
:
0: from all lookup local
32766: from all lookup main
32767: from all lookup default
When you do ip route show
you show the "main" table as default. You can show one of the other tables by adding table $name
, e.g.:
$ ip route show table local
broadcast 127.0.0.0 dev lo proto kernel scope link src 127.0.0.1
local 127.0.0.0/8 dev lo proto kernel scope host src 127.0.0.1
local 127.0.0.1 dev lo proto kernel scope host src 127.0.0.1
broadcast 127.255.255.255 dev lo proto kernel scope link src 127.0.0.1
broadcast 192.168.0.0 dev eth0 proto kernel scope link src 192.168.1.27
local 192.168.1.27 dev eth0 proto kernel scope host src 192.168.1.27
broadcast 192.168.1.255 dev eth0 proto kernel scope link src 192.168.1.27
You can add your own tables; edit /etc/iproute2/rt_tables
and add two lines:
11 WAN1
12 WAN2
Now you can add the default routes over ETH01 and ETH02 to the respective tables:
# ip route add default via 192.168.2.254 table WAN1
# ip route add default via 192.168.1.254 table WAN2
(You first describe ETH01 as having 192.168.1.254 as gateway and ETH02 and having 192.168.2.254 but then your ip route show
output disagrees, so I'm going with the latter... aside from the ETH1 / ETH01 difference.)
Now you need to add a rule to use the WAN1 table for traffic coming in from the second webserver IP address:
# ip rule add from 192.168.241.24 lookup WAN1 prio 1000
Now, when traffic comes in from ETH01 and gets sent via DNAT to the second IP address of the webserver, the webserver will return packets from that address and the rule will match that address and send return traffic via ETH01.
You don't really need the WAN2 table in this scenario, however if the router system itself needs to be accessible from both WAN interfaces, or if you want to be able to choose what WAN interface for whatever then it's useful to have it.
The issue technically isn't that they go out via the default gateway, but that NAT changes their source IP to that of the default gateway's interface. This is different from the destination IP that the connection was originally established on, and thus is not recognised as the same connection by the remote computer.
â CyberJacob
Jan 23 at 16:08
Some generic (but a bit outdated) infos there: lartc.org/howto/lartc.rpdb.multiple-links.html @wurtel I think you wrotedev ETH01
when you wanted to writetable ETH01
. I'd rather avoid naming the table with the name of the interface, it might confuse (I usually don't bother to name them, I just use the numbers)
â A.B
Jan 23 at 21:18
@CyberJacob there's an RFC (I can't find which right now) that says that an internet connection provider should not accept packets from their clients with source addresses that do not originate from within their address space, to combat spoofing of such addresses, so even if the NAT would set the source IP to the correct one, if the packet goes out through the wrong interface, it probably won't arrive at the destination anyway.
â wurtel
Jan 24 at 7:01
add a comment |Â
up vote
2
down vote
up vote
2
down vote
The problem with such a dual-homed setup is that the return packets originating from the webserver on the ETH0 network follow the default gateway, which is only correct for connections coming in through that interface. I've run into this myself.
The solution I use is to add an extra IP address to the webserver on the ETH0 network (I'm assuming 192.168.241.24), and use that as the DNAT target for connections coming in through the second WAN interface. Then add a routing rule that the second IP address gets routed out through the second WAN interface.
You need to understand a little bit about Linux policy based routing. Do ip rule show
:
0: from all lookup local
32766: from all lookup main
32767: from all lookup default
When you do ip route show
you show the "main" table as default. You can show one of the other tables by adding table $name
, e.g.:
$ ip route show table local
broadcast 127.0.0.0 dev lo proto kernel scope link src 127.0.0.1
local 127.0.0.0/8 dev lo proto kernel scope host src 127.0.0.1
local 127.0.0.1 dev lo proto kernel scope host src 127.0.0.1
broadcast 127.255.255.255 dev lo proto kernel scope link src 127.0.0.1
broadcast 192.168.0.0 dev eth0 proto kernel scope link src 192.168.1.27
local 192.168.1.27 dev eth0 proto kernel scope host src 192.168.1.27
broadcast 192.168.1.255 dev eth0 proto kernel scope link src 192.168.1.27
You can add your own tables; edit /etc/iproute2/rt_tables
and add two lines:
11 WAN1
12 WAN2
Now you can add the default routes over ETH01 and ETH02 to the respective tables:
# ip route add default via 192.168.2.254 table WAN1
# ip route add default via 192.168.1.254 table WAN2
(You first describe ETH01 as having 192.168.1.254 as gateway and ETH02 and having 192.168.2.254 but then your ip route show
output disagrees, so I'm going with the latter... aside from the ETH1 / ETH01 difference.)
Now you need to add a rule to use the WAN1 table for traffic coming in from the second webserver IP address:
# ip rule add from 192.168.241.24 lookup WAN1 prio 1000
Now, when traffic comes in from ETH01 and gets sent via DNAT to the second IP address of the webserver, the webserver will return packets from that address and the rule will match that address and send return traffic via ETH01.
You don't really need the WAN2 table in this scenario, however if the router system itself needs to be accessible from both WAN interfaces, or if you want to be able to choose what WAN interface for whatever then it's useful to have it.
The problem with such a dual-homed setup is that the return packets originating from the webserver on the ETH0 network follow the default gateway, which is only correct for connections coming in through that interface. I've run into this myself.
The solution I use is to add an extra IP address to the webserver on the ETH0 network (I'm assuming 192.168.241.24), and use that as the DNAT target for connections coming in through the second WAN interface. Then add a routing rule that the second IP address gets routed out through the second WAN interface.
You need to understand a little bit about Linux policy based routing. Do ip rule show
:
0: from all lookup local
32766: from all lookup main
32767: from all lookup default
When you do ip route show
you show the "main" table as default. You can show one of the other tables by adding table $name
, e.g.:
$ ip route show table local
broadcast 127.0.0.0 dev lo proto kernel scope link src 127.0.0.1
local 127.0.0.0/8 dev lo proto kernel scope host src 127.0.0.1
local 127.0.0.1 dev lo proto kernel scope host src 127.0.0.1
broadcast 127.255.255.255 dev lo proto kernel scope link src 127.0.0.1
broadcast 192.168.0.0 dev eth0 proto kernel scope link src 192.168.1.27
local 192.168.1.27 dev eth0 proto kernel scope host src 192.168.1.27
broadcast 192.168.1.255 dev eth0 proto kernel scope link src 192.168.1.27
You can add your own tables; edit /etc/iproute2/rt_tables
and add two lines:
11 WAN1
12 WAN2
Now you can add the default routes over ETH01 and ETH02 to the respective tables:
# ip route add default via 192.168.2.254 table WAN1
# ip route add default via 192.168.1.254 table WAN2
(You first describe ETH01 as having 192.168.1.254 as gateway and ETH02 and having 192.168.2.254 but then your ip route show
output disagrees, so I'm going with the latter... aside from the ETH1 / ETH01 difference.)
Now you need to add a rule to use the WAN1 table for traffic coming in from the second webserver IP address:
# ip rule add from 192.168.241.24 lookup WAN1 prio 1000
Now, when traffic comes in from ETH01 and gets sent via DNAT to the second IP address of the webserver, the webserver will return packets from that address and the rule will match that address and send return traffic via ETH01.
You don't really need the WAN2 table in this scenario, however if the router system itself needs to be accessible from both WAN interfaces, or if you want to be able to choose what WAN interface for whatever then it's useful to have it.
edited Jan 24 at 6:57
answered Jan 23 at 15:38
wurtel
9,25011024
9,25011024
The issue technically isn't that they go out via the default gateway, but that NAT changes their source IP to that of the default gateway's interface. This is different from the destination IP that the connection was originally established on, and thus is not recognised as the same connection by the remote computer.
â CyberJacob
Jan 23 at 16:08
Some generic (but a bit outdated) infos there: lartc.org/howto/lartc.rpdb.multiple-links.html @wurtel I think you wrotedev ETH01
when you wanted to writetable ETH01
. I'd rather avoid naming the table with the name of the interface, it might confuse (I usually don't bother to name them, I just use the numbers)
â A.B
Jan 23 at 21:18
@CyberJacob there's an RFC (I can't find which right now) that says that an internet connection provider should not accept packets from their clients with source addresses that do not originate from within their address space, to combat spoofing of such addresses, so even if the NAT would set the source IP to the correct one, if the packet goes out through the wrong interface, it probably won't arrive at the destination anyway.
â wurtel
Jan 24 at 7:01
add a comment |Â
The issue technically isn't that they go out via the default gateway, but that NAT changes their source IP to that of the default gateway's interface. This is different from the destination IP that the connection was originally established on, and thus is not recognised as the same connection by the remote computer.
â CyberJacob
Jan 23 at 16:08
Some generic (but a bit outdated) infos there: lartc.org/howto/lartc.rpdb.multiple-links.html @wurtel I think you wrotedev ETH01
when you wanted to writetable ETH01
. I'd rather avoid naming the table with the name of the interface, it might confuse (I usually don't bother to name them, I just use the numbers)
â A.B
Jan 23 at 21:18
@CyberJacob there's an RFC (I can't find which right now) that says that an internet connection provider should not accept packets from their clients with source addresses that do not originate from within their address space, to combat spoofing of such addresses, so even if the NAT would set the source IP to the correct one, if the packet goes out through the wrong interface, it probably won't arrive at the destination anyway.
â wurtel
Jan 24 at 7:01
The issue technically isn't that they go out via the default gateway, but that NAT changes their source IP to that of the default gateway's interface. This is different from the destination IP that the connection was originally established on, and thus is not recognised as the same connection by the remote computer.
â CyberJacob
Jan 23 at 16:08
The issue technically isn't that they go out via the default gateway, but that NAT changes their source IP to that of the default gateway's interface. This is different from the destination IP that the connection was originally established on, and thus is not recognised as the same connection by the remote computer.
â CyberJacob
Jan 23 at 16:08
Some generic (but a bit outdated) infos there: lartc.org/howto/lartc.rpdb.multiple-links.html @wurtel I think you wrote
dev ETH01
when you wanted to write table ETH01
. I'd rather avoid naming the table with the name of the interface, it might confuse (I usually don't bother to name them, I just use the numbers)â A.B
Jan 23 at 21:18
Some generic (but a bit outdated) infos there: lartc.org/howto/lartc.rpdb.multiple-links.html @wurtel I think you wrote
dev ETH01
when you wanted to write table ETH01
. I'd rather avoid naming the table with the name of the interface, it might confuse (I usually don't bother to name them, I just use the numbers)â A.B
Jan 23 at 21:18
@CyberJacob there's an RFC (I can't find which right now) that says that an internet connection provider should not accept packets from their clients with source addresses that do not originate from within their address space, to combat spoofing of such addresses, so even if the NAT would set the source IP to the correct one, if the packet goes out through the wrong interface, it probably won't arrive at the destination anyway.
â wurtel
Jan 24 at 7:01
@CyberJacob there's an RFC (I can't find which right now) that says that an internet connection provider should not accept packets from their clients with source addresses that do not originate from within their address space, to combat spoofing of such addresses, so even if the NAT would set the source IP to the correct one, if the packet goes out through the wrong interface, it probably won't arrive at the destination anyway.
â wurtel
Jan 24 at 7:01
add a comment |Â
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Please show us the routing tables of both router and web server. Use the command
ip addr show; ip route show
on both serversâ andcoz
Jan 23 at 10:17
Is the router set up to NAT between the LAN and WANs?
â CyberJacob
Jan 23 at 10:24
Added the requested routing tables and yes, NAT is enabled and working fine.
â Sierramike
Jan 23 at 14:06