mjhjmtu

I'm configuring a GNU/Linux Router with Debian Stretch (9.7) and before rebooting the server, all traffic from one interface to another was going ok, but after that, I received a message like this (tty):

enp1s6: Something Wicked happened! ffff.

I have a host on the same switch and same network, for testing purposes, and basically, the LAN of the Router is not answering to echo requests.

Here goes some information about the server.

kernel.log

Jan 25 08:58:02 server001 kernel: [25060.494127] enp1s6: Link changed: 
Jan 25 08:58:02 server001 kernel: [25060.494127] 100Mbps, half duplex
Jan 25 08:58:02 server001 kernel: [25060.494254] enp1s6: Something Wicked happened! ffff.
Jan 25 08:58:02 server001 kernel: [25060.497338] enp1s6: Link up
Jan 25 08:58:02 server001 kernel: [25060.497557] enp1s6: Link changed: 
Jan 25 08:58:02 server001 kernel: [25060.497557] 100Mbps, full duplex
Jan 25 08:58:02 server001 kernel: [25060.499986] enp1s6: Link up
Jan 25 08:58:02 server001 kernel: [25060.500206] enp1s6: Link changed: 
Jan 25 08:58:02 server001 kernel: [25060.500206] 100Mbps, full duplex
Jan 25 08:58:02 server001 kernel: [25060.500447] enp1s6: Link up
Jan 25 08:58:02 server001 kernel: [25060.500667] enp1s6: Link changed: 
Jan 25 08:58:02 server001 kernel: [25060.500667] 100Mbps, full duplex
Jan 25 08:58:02 server001 kernel: [25060.500895] enp1s6: Link up
Jan 25 08:58:02 server001 kernel: [25060.501114] enp1s6: Link changed: 
Jan 25 08:58:02 server001 kernel: [25060.501114] 10Mbps, full duplex
Jan 25 08:58:02 server001 kernel: [25060.501341] enp1s6: Link up
Jan 25 08:58:02 server001 kernel: [25060.501559] enp1s6: Link changed: 
Jan 25 08:58:02 server001 kernel: [25060.501559] 100Mbps, full duplex
Jan 25 08:58:02 server001 kernel: [25060.503985] enp1s6: Link up
Jan 25 08:58:02 server001 kernel: [25060.504204] enp1s6: Link changed: 
Jan 25 08:58:02 server001 kernel: [25060.504204] 100Mbps, full duplex
Jan 25 08:58:02 server001 kernel: [25060.504326] enp1s6: Something Wicked happened! ffff.
Jan 25 08:58:02 server001 kernel: [25060.529009] enp1s6: Link up
Jan 25 08:58:02 server001 kernel: [25060.529229] enp1s6: Link changed: 
Jan 25 08:58:02 server001 kernel: [25060.529230] 100Mbps, full duplex
Jan 25 08:58:02 server001 kernel: [25060.529484] enp1s6: Link up
Jan 25 08:58:02 server001 kernel: [25060.529732] enp1s6: Link changed: 
Jan 25 08:58:02 server001 kernel: [25060.529735] 100Mbps, full duplex
Jan 25 08:58:02 server001 kernel: [25060.531075] enp1s6: Link up
Jan 25 08:58:02 server001 kernel: [25060.531295] enp1s6: Link changed: 
Jan 25 08:58:02 server001 kernel: [25060.531296] 100Mbps, half duplex
Jan 25 08:58:02 server001 kernel: [25060.531531] enp1s6: Link up
Jan 25 08:58:02 server001 kernel: [25060.531751] enp1s6: Link changed: 
Jan 25 08:58:02 server001 kernel: [25060.531751] 100Mbps, full duplex
Jan 25 08:58:02 server001 kernel: [25060.531977] enp1s6: Link up
Jan 25 08:58:02 server001 kernel: [25060.532196] enp1s6: Link changed: 
Jan 25 08:58:02 server001 kernel: [25060.532196] 100Mbps, half duplex
Jan 25 08:58:02 server001 kernel: [25060.532422] enp1s6: Link up
Jan 25 08:58:02 server001 kernel: [25060.532642] enp1s6: Link changed: 
Jan 25 08:58:02 server001 kernel: [25060.532642] 100Mbps, full duplex
Jan 25 08:58:02 server001 kernel: [25060.532869] enp1s6: Link up
Jan 25 08:58:02 server001 kernel: [25060.533089] enp1s6: Link changed: 
Jan 25 08:58:02 server001 kernel: [25060.533090] 100Mbps, full duplex
Jan 25 08:58:02 server001 kernel: [25060.533214] enp1s6: Something Wicked happened! ffff.

lspci (nics): enp0s7 + enp1s6

00:07.0 Bridge: NVIDIA Corporation MCP61 Ethernet (rev a2)
 Subsystem: Gigabyte Technology Co., Ltd MCP61 Ethernet
 Flags: bus master, 66MHz, fast devsel, latency 0, IRQ 24, NUMA node 0
 Memory at fe02d000 (32-bit, non-prefetchable) [size=4K]
 I/O ports at f000 [size=8]
 Capabilities: [44] Power Management version 2
 Capabilities: [50] MSI: Enable+ Count=1/8 Maskable+ 64bit+
 Capabilities: [6c] HyperTransport: MSI Mapping Enable- Fixed+
 Kernel driver in use: forcedeth
 Kernel modules: forcedeth

01:06.0 Ethernet controller: Sundance Technology Inc / IC Plus Corp IC Plus IP100A Integrated 10/100 Ethernet MAC + PHY (rev 31)
 Flags: bus master, medium devsel, latency 0, IRQ 16, NUMA node 0
 I/O ports at b000 [size=128]
 Memory at fde00000 (32-bit, non-prefetchable) [size=512]
 [virtual] Expansion ROM at fdf00000 [disabled] [size=64K]
 Capabilities: [50] Power Management version 2
 Kernel driver in use: sundance
 Kernel modules: sundance

ethtool

Settings for enp0s7:
 Supported ports: [ MII ]
 Supported link modes: 10baseT/Half 10baseT/Full 
 100baseT/Half 100baseT/Full 
 1000baseT/Full 
 Supported pause frame use: No
 Supports auto-negotiation: Yes
 Advertised link modes: 10baseT/Half 10baseT/Full 
 100baseT/Half 100baseT/Full 
 1000baseT/Full 
 Advertised pause frame use: No
 Advertised auto-negotiation: Yes
 Speed: 100Mb/s
 Duplex: Full
 Port: MII
 PHYAD: 3
 Transceiver: external
 Auto-negotiation: on
 Supports Wake-on: g
 Wake-on: d
 Link detected: yes

Settings for enp1s6:
 Supported ports: [ TP MII ]
 Supported link modes: 10baseT/Half 10baseT/Full 
 100baseT/Half 100baseT/Full 
 Supported pause frame use: No
 Supports auto-negotiation: Yes
 Advertised link modes: Not reported
 Advertised pause frame use: No
 Advertised auto-negotiation: No
 Speed: 100Mb/s
 Duplex: Full
 Port: MII
 PHYAD: 0
 Transceiver: internal
 Auto-negotiation: off
 Supports Wake-on: pg
 Wake-on: d
 Current message level: 0x00000001 (1)
 drv
 Link detected: yes

ethtool statistics (enp1s6)

NIC statistics:
 tx_multiple_collisions: 26010
 tx_single_collisions: 27540
 tx_late_collisions: 5100
 tx_deferred: 27030
 tx_deferred_excessive: 26010
 tx_aborted: 6630
 tx_bcasts: 27030
 rx_bcasts: 27032
 tx_mcasts: 5610
 rx_mcasts: 27285

ip addr show

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
 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: enp1s6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN group default qlen 1000
 link/ether 84:16:84:16:84:16 brd ff:ff:ff:ff:ff:ff
 inet 192.168.1.1/24 brd 192.168.1.255 scope global enp1s6
 valid_lft forever preferred_lft forever
3: enp0s7: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
 link/ether 50:e5:49:64:f6:8b brd ff:ff:ff:ff:ff:ff
 inet 192.168.0.12/24 brd 192.168.0.255 scope global enp0s7
 valid_lft forever preferred_lft forever

lsmod

Module Size Used by
ip6table_filter 16384 0
ip6_tables 28672 1 ip6table_filter
xt_conntrack 16384 2
nf_conntrack_netlink 36864 0
nfnetlink 16384 6 nf_conntrack_netlink
iptable_filter 16384 1
ipt_MASQUERADE 16384 1
nf_nat_masquerade_ipv4 16384 1 ipt_MASQUERADE
iptable_nat 16384 1
nf_conntrack_ipv4 16384 3
nf_defrag_ipv4 16384 1 nf_conntrack_ipv4
nf_nat_ipv4 16384 1 iptable_nat
nf_nat 24576 2 nf_nat_masquerade_ipv4,nf_nat_ipv4
nf_conntrack 114688 6 nf_conntrack_ipv4,nf_conntrack_netlink,nf_nat_masquerade_ipv4,xt_conntrack,nf_nat_ipv4,nf_nat
snd_hda_codec_realtek 90112 1
snd_hda_codec_generic 69632 1 snd_hda_codec_realtek
edac_mce_amd 28672 0
edac_core 57344 0
kvm 598016 0
evdev 24576 2
ppdev 20480 0
serio_raw 16384 0
nouveau 1556480 1
joydev 20480 0
snd_hda_intel 36864 0
mxm_wmi 16384 1 nouveau
snd_hda_codec 135168 3 snd_hda_intel,snd_hda_codec_generic,snd_hda_codec_realtek
wmi 16384 2 mxm_wmi,nouveau
snd_hda_core 86016 4 snd_hda_intel,snd_hda_codec,snd_hda_codec_generic,snd_hda_codec_realtek
video 40960 1 nouveau
snd_hwdep 16384 1 snd_hda_codec
ttm 98304 1 nouveau
drm_kms_helper 155648 1 nouveau
drm 360448 4 nouveau,ttm,drm_kms_helper
snd_pcm 110592 3 snd_hda_intel,snd_hda_codec,snd_hda_core
irqbypass 16384 1 kvm
sg 32768 0
pcspkr 16384 0
k10temp 16384 0
parport_pc 28672 0
parport 49152 2 parport_pc,ppdev
i2c_algo_bit 16384 1 nouveau
button 16384 1 nouveau
snd_timer 32768 1 snd_pcm
snd 86016 7 snd_hda_intel,snd_hwdep,snd_hda_codec,snd_timer,snd_hda_codec_generic,snd_hdacodec_realtek,snd_pcm
soundcore 16384 1 snd
acpi_cpufreq 20480 0
ip_tables 24576 3 iptable_filter,iptable_nat
x_tables 36864 6 ip_tables,iptable_filter,ipt_MASQUERADE,ip6table_filter,xt_conntrack,ip6_tables
autofs4 40960 2
ext4 585728 2
crc16 16384 1 ext4
jbd2 106496 1 ext4
fscrypto 28672 1 ext4
ecb 16384 0
glue_helper 16384 0
lrw 16384 0
gf128mul 16384 1 lrw
ablk_helper 16384 0
cryptd 24576 1 ablk_helper
aes_x86_64 20480 1
mbcache 16384 3 ext4
raid10 49152 0
raid456 106496 0
async_raid6_recov 20480 1 raid456
async_memcpy 16384 2 raid456,async_raid6_recov
async_pq 16384 2 raid456,async_raid6_recov
async_xor 16384 3 async_pq,raid456,async_raid6_recov
async_tx 16384 5 async_xor,async_pq,raid456,async_memcpy,async_raid6_recov
xor 24576 1 async_xor
raid6_pq 110592 3 async_pq,raid456,async_raid6_recov
libcrc32c 16384 1 raid456
crc32c_generic 16384 3
raid0 20480 0
multipath 16384 0
linear 16384 0
raid1 36864 1
md_mod 135168 6 raid1,raid10,multipath,linear,raid0,raid456
sd_mod 49152 7
hid_generic 16384 0
usbhid 53248 0
hid 122880 2 hid_generic,usbhid
ata_generic 16384 0
ohci_pci 16384 0
psmouse 135168 0
sata_nv 28672 5
forcedeth 69632 0
ehci_pci 16384 0
libata 249856 2 ata_generic,sata_nv
ohci_hcd 53248 1 ohci_pci
ehci_hcd 81920 1 ehci_pci
scsi_mod 225280 3 sd_mod,libata,sg
usbcore 253952 5 usbhid,ehci_hcd,ohci_pci,ohci_hcd,ehci_pci
sundance 32768 0
mii 16384 1 sundance
usb_common 16384 1 usbcore
i2c_nforce2 16384 0

Any guesses?

Please, be patient: I'm a former SysAdmin (since years), nowadays Software Developer.

It appears your Sundance 10/100 NIC is old, perhaps too old...

See https://bugzilla.redhat.com/show_bug.cgi?id=748973 (f16 Sundance 10/100 Ethernet module crashes when plugged into gigabit router)

Per your ethtool output, I notice enp1s6 is not reporting as supporting auto-negotiation. Is that disabled on the device/port you are connecting too? If possible adjust the device you are connecting with to have auto-negotiation enabled. If you don't have access to that device, or you don't want to change it, then you may have to force a speed/duplix on enp1s6.