secondary IP on wg0 fails

Roman Mamedov rm at
Sat May 8 16:50:39 UTC 2021

On Sat, 8 May 2021 17:31:58 +0100
lejeczek <peljasz at> wrote:

> I'm experiencing a pretty weird wireguard, or perhaps 
> kernel/OS stack bits behavior.
> I have three nodes which all can ping each other on wg0's 
> IPs but when I add a secondary IP:
> -> $ ip addr add dev wg0
> it gets weird, namely, say when that sec IP is on
> A -> B ping returns; C ping waits, no errors, no return
> B -> both C & A pings return
> C -> neither A nor B ping returns
> I'm on CentOS with 4.18.0-301.1.el8.x86_64.
> All three nodes are virtually identical kvm VMs.
> any suggestions as to what is not working here or how to 
> troubleshoot are vey appreciated.
> many thanks, L.

Did you add the new IP to AllowedIPs of that node on all the other nodes?

Also remember that sets of AllowedIPs should be unique within the network,
i.e. can't have the same AllowedIPs or ranges listed for multiple nodes at the
same time. Setting it to the same /24 on all nodes will not work.

If still not clear, better post your complete config (without keys).

With respect,

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