Lan Interface randomly goes down

[caplam]

Hello,

Yesterday i upgraded to 25.7.5.
In the evening, i was looking at a film from my plex server and experienced connections issues.
The plex server in the vlan 30. The plex player (apple tv) is in lan (igc1 interface).
I never had this before.
I found nothing in the logs that could explain that.
The link on igc1 (lan) goes down.
Could you give me a hint where to look ?

here i the log from system/general

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2025-10-15T23:45:35Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure dns (execute task : unbound_configure_do())
2025-10-15T23:45:35Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure dns (execute task : dnsmasq_configure_do())
2025-10-15T23:45:35Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure dns ()
2025-10-15T23:45:35Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure dhcp (execute task : radvd_configure_dhcp())
2025-10-15T23:45:35Warningopnsense/usr/local/etc/rc.linkup: dhcpd_dhcp6_configure() found no suitable IPv6 address on opt3(vlan0.20)
2025-10-15T23:45:35Warningopnsense/usr/local/etc/rc.linkup: dhcpd_dhcp6_configure() found no suitable IPv6 address on lan(igc1)
2025-10-15T23:45:35Warningopnsense/usr/local/etc/rc.linkup: dhcpd_dhcp6_configure() found no suitable IPv6 address on opt2(vlan0.10)
2025-10-15T23:45:35Warningopnsense/usr/local/etc/rc.linkup: dhcpd_dhcp6_configure() found no suitable IPv6 address on opt1(vlan0.9)
2025-10-15T23:45:35Warningopnsense/usr/local/etc/rc.linkup: dhcpd_dhcp6_configure() found no suitable IPv6 address on opt5(vlan0.40)
2025-10-15T23:45:35Warningopnsense/usr/local/etc/rc.linkup: dhcpd_dhcp6_configure() found no suitable IPv6 address on opt4(vlan0.30)
2025-10-15T23:45:35Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure dhcp (execute task : dhcpd_dhcp_configure())
2025-10-15T23:45:35Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure dhcp ()
2025-10-15T23:45:35Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure ipsec (execute task : ipsec_configure_do(,lan))
2025-10-15T23:45:35Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure ipsec (,lan)
2025-10-15T23:45:35Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure monitor (execute task : dpinger_configure_do(,[]))
2025-10-15T23:45:35Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure monitor (,[])
2025-10-15T23:45:35Noticeopnsense/usr/local/etc/rc.linkup: ROUTING: entering configure using lan
2025-10-15T23:45:35Noticekernel<6>[35632] igc1: link state changed to UP
2025-10-15T23:45:35Noticeopnsense/usr/local/etc/rc.linkup: DEVD: Ethernet attached event for lan(igc1)
2025-10-15T23:45:31Noticeopnsense/usr/local/etc/rc.linkup: DEVD: Ethernet detached event for lan(igc1)
2025-10-15T23:45:31Noticekernel<6>[35628] igc1: link state changed to DOWN
2025-10-15T23:41:04Noticekernel<6>[35361] arp: 192.168.2.52 moved from 02:6c:29:76:9a:a8 to 24:8a:07:d3:ea:b0 on igc1
2025-10-15T23:40:59Noticekernel<6>[35356] arp: 192.168.2.52 moved from 24:8a:07:d3:ea:b0 to a0:d3:c1:34:03:e6 on igc1
2025-10-15T23:40:50Noticekernel<6>[35348] arp: 192.168.2.50 moved from 02:8d:24:b7:27:0e to 58:47:ca:74:70:2b on igc1
2025-10-15T23:40:48Noticesyslog-ngSyslog connection broken; fd='34', server='AF_INET(192.168.2.50:1514)', time_reopen='60'
2025-10-15T23:40:48Errorsyslog-ngI/O error occurred while writing; fd='34', error='Host is down (64)'
2025-10-15T23:40:48Noticesyslog-ngSyslog connection established; fd='34', server='AF_INET(192.168.2.50:1514)', local='AF_INET(0.0.0.0:0)'
2025-10-15T23:40:13Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure newwanip:rfc2136 (,[lan])
2025-10-15T23:40:11Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure dns (execute task : unbound_configure_do())
2025-10-15T23:40:11Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure dns (execute task : dnsmasq_configure_do())
2025-10-15T23:40:11Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure dns ()
2025-10-15T23:40:11Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure dhcp (execute task : radvd_configure_dhcp())
2025-10-15T23:40:11Warningopnsense/usr/local/etc/rc.linkup: dhcpd_dhcp6_configure() found no suitable IPv6 address on opt3(vlan0.20)
2025-10-15T23:40:11Warningopnsense/usr/local/etc/rc.linkup: dhcpd_dhcp6_configure() found no suitable IPv6 address on lan(igc1)
2025-10-15T23:40:11Warningopnsense/usr/local/etc/rc.linkup: dhcpd_dhcp6_configure() found no suitable IPv6 address on opt2(vlan0.10)
2025-10-15T23:40:11Warningopnsense/usr/local/etc/rc.linkup: dhcpd_dhcp6_configure() found no suitable IPv6 address on opt1(vlan0.9)
2025-10-15T23:40:11Warningopnsense/usr/local/etc/rc.linkup: dhcpd_dhcp6_configure() found no suitable IPv6 address on opt5(vlan0.40)
2025-10-15T23:40:11Warningopnsense/usr/local/etc/rc.linkup: dhcpd_dhcp6_configure() found no suitable IPv6 address on opt4(vlan0.30)
2025-10-15T23:40:11Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure dhcp (execute task : dhcpd_dhcp_configure())
2025-10-15T23:40:11Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure dhcp ()
2025-10-15T23:40:11Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure ipsec (execute task : ipsec_configure_do(,lan))
2025-10-15T23:40:11Noticeopnsense/usr/local/etc/rc.linkup: plugins_configure ipsec (,lan)
My opnsense hardware is a intel N100 box.
igc0 is Wan with (pppoe on vlan)
igc1 is Lan
all the vlans (9, 10, 20, 30, 40) are on a lagg of igc2 and igc3

[franco]

Well, igc1 physically disconnected for 4 seconds as witnessed by the kernel:

2025-10-15T23:45:35Noticekernel<6>[35632] igc1: link state changed to UP
2025-10-15T23:45:35Noticeopnsense/usr/local/etc/rc.linkup: DEVD: Ethernet attached event for lan(igc1)
2025-10-15T23:45:31Noticeopnsense/usr/local/etc/rc.linkup: DEVD: Ethernet detached event for lan(igc1)
2025-10-15T23:45:31Noticekernel<6>[35628] igc1: link state changed to DOWN

Not sure why. 4 seconds is a bit too short for a switch reboot.


Cheers,
Fraco

[caplam]

Thank for your answer.
Finally seems to be my patch cable.
Yesterday i moved my router to change a defective usb cable (for a kvm hid).
This morning i plug the new usb cable and noticed that led on the switch interface attached to lan (igc1) went off. And when i slightly move the cable it goes off. The interface are sfp+ 2,5G ethernet modules.
These patch cables are way to rigid and i guess not very good quality.
I ordered new cables for all my router interfaces.

[BrandyWine]

igc for SFP?
What hardware is it exactly?

[caplam]

On router interfaces are ethernet 2,5G
SFP+ are on switch.

[Patrick M. Hausen]

Many SFP+ will not negotiate at 2.5G. Try locking the interfaces to 1G on the OPNsense side.

[BrandyWine]

What Patrick says is likely the issue, but, two things must be done, 1) disable ASPM on fw device (any way you can, bios, os settings, etc), 2) flash the latest firmware onto your (presumably) i226 nics.

And next is, what sfp modules are they exactly? Are they fully supported by switch firmware? Any updates available for switch?

I think another user had same issue, but sfp was on fw, and noticed switch would say one speed while fw said it was at another.

The i226 is pretty solid running 2.5G. If new cables don't solve the problem then I would be looking at SFP side.

[caplam]

I changed the patch cables and so far i had no more issues.
I try to move the cable and it seems better locked than the old one.
The switch is a chinese one (sks8300-8x). I found a new firmware.
On this switch i have several sfp+ modules some are fiber modules with lc connectors and some have RJ45 connectors.
The Lan is the one that had troubles. Speed is displayed at 2,5G
The two in lacp for vlans are displayed at 10G on the switch.

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Ethernet1/0/1 usw48         Enabled fiber-auto 10G/Full Disabled auto
Ethernet1/0/2 vlans-router Enabled fiber-auto 10G/Full Disabled auto
Ethernet1/0/3 vlans-router Enabled fiber-auto 10G/Full Disabled auto
Ethernet1/0/4 lan-router Enabled fiber-auto 2500M/Full Disabled auto
Ethernet1/0/5 godzilla-eth1 Enabled fiber-auto 10G/Full Disabled auto
Ethernet1/0/6 godzilla-eth0 Enabled fiber-auto 10G/Full Disabled auto
Ethernet1/0/7 uplink-et3 Enabled fiber-auto Link Down Disabled auto
Ethernet1/0/8 uplink-et1 Enabled fiber-auto Link Down Disabled auto
Port-Channel1 vlans         Enabled Auto/Auto 20G/Full Disabled auto
1/0/1 is dac cable to unifi switch
1/0/2 is RJ45 module to i226v router
1/0/3 is RJ45 module to i226v router
1/0/4 is RJ45 module to i226v router
1/0/5 is sfp fiber module to sfp on server
1/0/6 is sfp fiber module to sfp on server

1/0/7 & 8 are down i moved these module on the unifi switch (links to other floors)