dhcpd sending on the same IP it receives on
bakers at web-ster.com
Tue Feb 5 18:37:33 UTC 2008
Jared Gillis wrote:
> I am having a similar problem as initially discussed in this thread:
> I have a linux DHCP server that has two uplinks, each of which goes to a
> router that is relaying DHCP requests to the DHCP server. Router A is on
> eth0, Router B is on eth1. The DHCP server's default gateway points at
> Router A. There is a very small corner case in which this causes a problem:
> Router B gets a broadcast DHCPDISCOVER, and relays the request to the
> DHCP server, then takes the reply and hands it to the client. The
> client's DHCP implementation then switches to unicast for further DHCP
> traffic, sending to the server's eth1 address. The client sends a
> DHCPREQUEST packet to the server to renew the lease, and the server
> replies, but from eth0's IP address.
> This *is* broken, as we are talking about unicast IP traffic, and if the
> DHCP client happens to be behind a stateful packet inspection firewall,
> the DHCP reply gets dropped, and the client never receives the response.
> I looked into the local-address configuration option, but since we are
> answering DHCP requests on both interfaces, that would mean we'd have to
> run two daemons, which is not a good solution for us.
> Does anyone know of a workaround/fix for this, and if not, where can I
> submit a bug report? =)
That seems like a semi-complex setup for just one server. Wouldn't
it be easier to just run two different (physical) servers for that
odd corner case you're running in to?
Scott Baker - Canby Telcom
RHCE - System Administrator - 503.266.8253
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