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

Code Select Expand

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?