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Re: IPv4 networking problem after dist-upgrade



Oleg wrote: 
> I've updated my server to bullseye a couple of days ago and since then I'm
> unable to get IPv4 networking to work properly again. IPv6 still seems to work
> like charm. I can also connect to the hosted VMs (KVM via libvirt) on the
> server over IPv4 without problems. However, when I try to address the server
> directly, all packets seem to be dropped on the outgoing interface. If, for
> instance, I ping the server, I can see the ICMPv4 echo requests _and_ replies
> in tcpdump, but the pinging peer won't never receive the replies. If I check
> the ARP tables I can find the gateway's MAC address tagged as DELAY. 
> 
> The general setup has worked before the dist-upgrade for years and I'm a bit
> clueless what might has been broken during the update.

Can you tell us about networking on the host, please?

ip link show

ip addr show

ip route show

cat /proc/sys/net/ipv4/ip_forward

would be a good start. Also, are you running a firewall of any
kind on the server itself?

-dsr-


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