Post #830965

2026-03-26 13:25 UTC

#FreeBSD folk - calling for your help! Upgrading a server with broadcom NICs to 15.0-RELEASE causes VNET jails to stop resolving DNS names. Even trying direct drill freebsd.org fails. Can't even resolve local names. Pinging IPs - fine. Just no DNS resolution. Rolling back to 14.3 the jails work again. Putting a different brand NIC in (i.e. Intel) also resolves the problem. Seems to be a Broadcom only issue. Fresh 15.0-RELEASE install has the same issue too. I've had a forum discussion on the link below, where a lot of time was spent convincing people there's nothing wrong with my DNS servers https://forums.freebsd.org/threads/broadcom-nic-leads-to-vnet-jails-being-unable-to-make-dns-requests.101534/#post-751758 Any help appreciated! (But I'm probably just going to buy some Intel NICs) #BSD #RunBSD

Replies (4)

@meka@bsd.network 2026-03-26 13:34

@paul the bridge interface changed how it should be configured, namely IP address can not be set on a member, it has to be set on the bridge. Can that be the reason?

Open ##830971
@ltning@pleroma.anduin.net 2026-03-26 21:26

@paul We had issues with VLAN offloading being broken in jails on bridge on lagg on broadcom. Disabling offloading solved the issue. It looked the same - some traffic worked, other not. In particular fragments were a problem.

Open ##830972
@JdeBP@mastodonapp.uk 2026-03-26 18:09

@paul That's mad. Since you've eliminated the choice of DNS server as the problem locus, one thing to test is if this is protocol specific. Can you make TCP connections (using IP addresses, obviously) to anything from the jail via that NIC? What about talking to another UDP service, like SNTP? Crazy question: Your MAC addresses are unique, aren't they? The -n option to traceroute is definitely your friend, here, by the way. #FreeBSD #networking #Broadcom

Open ##1233949
@bodems@chaos.social 2026-03-27 05:22

@paul I had the same last year after an upgrade. I had to disable txcsum offloading on the jails interface in /etc/rc.conf: ifconfig_epair0b="-txcsum" checksum offloading on broadcom NICs are broken for UDP

Open ##1233950