server with two NICs and relayed to

Simon Hobson dhcp1 at
Tue Nov 10 17:29:27 UTC 2015

lejeczek <peljasz at> wrote:

> hi everybody
> Now, that second box has also a virtual NIC (libvirtd's bridge) and VMs guests are using it, traffic is routed via 1st NIC to that virtual net. This second box dhcrelays to the first box(dhcpd).
> I see box-dhcrelay forwards to box-dhcpd, I see box-dhcpd receives and offers a lease but that VM guest does not get it.

Follow the packets. Use your preferred packet sniffing tool to see where the packet gets lost. Does it leave the DHCP server ? Does it reach the other server ? Is there a firewall that might block it ? Does the relay log that it's received it ? Does it leave the (virtual) nic from the relay ? Does it reach the (virtual) nic on the client ?

All you know at the moment is "it doesn't work". Follow the trail, and then you'll know that it fails at a specific location and you can then try and work out why.

BTW - I don't like the sound of "policy routing", for almost every non-broken network it is not required.

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