Problems with NSD on multihome FreeBSD host

Sebastian Castro secastro at
Mon Apr 26 19:55:38 UTC 2004

Hi All:

I'm still working in my FreeBSD server to make it work with NSD.

I've already updated my ports with NSD 2.0.2 and it was pretty easy
(thanks to Peter Hessler).

My host has two network interfaces, with two IP addresses belonging to
two different IP networks (one for national traffic, one for
international traffic). Let's suppose first IP is X.X.X.X and second is

The default route is through first network interface.

When I query to first interface, I got the expected answer.

When I query to second interface, I got a query time out.

Checking out with tcpdump, I've found that queries coming through 2nd
interface (dst address Y.Y.Y.Y) went out through first interface (probably due to the default
router) but using as IP source address X.X.X.X, so any firewall will not
match the answer because is not "related".

If I force queries to be TCP, they work perfectly in both addresses.

I'm not sure if this is a problem related with NSD or FreeBSD. I'm
planning to solve it using SNAT (if FreeBSD allow it), but I still want
to hear from you (probably I'm doing something wrong).

Best Regards
Sebastian E. Castro Avila             sebastian at
Administrador de DNS, NIC Chile

Agustinas 1357 Piso 4  
Santiago, Chile Cod. Postal 6500587                   
Phone: +56-2-9407705                  Fax  : +56-2-9407701 

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