bind and address rewriting
Hello,
I have a linux box (Debian 2.2, kernel 2.2.17) running as an ISDN dial-on-
demand gateway to my ISP. The ISP is assigning dynamic IP adresses, and I
have address rewriting enabled (echo 2 > /proc/sys/net/ipv4/ip_dynaddr).
UDP packets from my internal network arriving for port 53 of the NS of my
ISP are masqueraded and routed through the ippp device.
On my main linux box (also Debian 2.2), I have a local caching-only
nameserver installed (bind8) which forwards to the NS of my IP.
Now, when bind tries to resolve a domain name and wants to connect to the
forwarding NS, the UDP packet is masqueraded correctly and triggers the
PPP dial-out to my ISP. But finally, the UDP packet gets dropped out there
because no address rewriting is done for UDP packets to match the newly
assigned IP address of the ippp interface.
bind seems to resend the request after one long minute has passed, but by
this time, my dial-on-demand configuration has closed the connection due
to inactivity on the link.
Is there something reasonable good to work around this? Since no address
rewriting is done for UDP packets, it would be an alternative to make bind
resend its requests much earlier than after one minute (say, 5 seconds or
so), but it seems to me that there is no option for setting the delay
between the retransmissions.
Does anybody has an idea about that?
Greetings,
Thomas
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