Bind9 + PPP problem

[P.B.]

Hi,

I've just set up my linux box as PPP DialUp Server and can connect and do
everything except resolve names. The Linux server is also running Bind for
several years now - without problems.

There are several interfaces in this server (eth, wlan, ppp0(~ISP) - and
when serving dialup clients, also ppp1). The installed DNS works properly
for ALL installed interfaces, EXCEPT for ppp1.


I've tried the following:

1) Iptables entries are the same for wlan (where DNS works). Also tried
dropping iptables: no change.
2) Checked connection by connecting by IP (instead of by name)
3) used tcpdump to see what's happening: DNS request coming in from
ppp-client, but no answer.
4) bind's logs: (turned everything on for debugging): Request from
ppp-client does not show up in the logs,
but all other requests do.
5) Changed named.conf to bind to interface ppp1's IP, too.
6) Setup pppd to give the ppp-client an external DNS: works properly - So
that's why I assume it's my DNS having problems.



....it seems like Bind is simply not receiving any requests from this
interface.