dhclient errors cause network to go down

[scopecat]

After upgrading to 26.1.1, I had an issue where connectivity would drop a few hours after my router's boot. I reverted to 25.7. I recently tried again to upgrade to 26.1.2 and encountered the same issue. I looked in the logs and found this section of dhclient that I think is relevant. I've downgraded again to 25.7 and am no longer experiencing this issue. Can anybody help me troubleshoot?

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2026-02-14T21:01:20 Notice dhclient dhclient-script: Reason PREINIT on vlan01.0.201 executing
2026-02-14T21:01:20 Notice dhclient dhclient-script: Reason EXPIRE on vlan01.0.201 executing
2026-02-14T21:01:07 Error dhclient send_packet: No buffer space available
2026-02-14T21:00:48 Error dhclient send_packet: No buffer space available
(Bigger log attached)

Thanks!

[scopecat]

I narrowed it down to Unbound. Restarting the unbound service fixes the issue.

In trying to diagnose this issue further, I ran into the following error message:

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[1779057884] unbound[8483:0] warning: setsockopt(..., SO_SNDBUF, ...) was not granted: No buffer space available
[1779057884] unbound[8483:0] warning: so-sndbuf 4194304 was not granted. Got 57344. To fix: start with root permissions(linux) or sysctl bigger net.core.wmem_max(linux) or kern.ipc.maxsockbuf(bsd) values. or set so-sndbuf: 0 (use system value).
Setting kern.ipc.maxsockbuf=8388608 seems to fix the failure. Does anyone know why unbound is asking for more buffer space than OPNSense is configured by default to give?