timeout on forwarder

Siegfried Hildebrand Siegfried.Hildebrand at FernUni-Hagen.de
Tue Nov 23 10:47:56 UTC 1999


> i'm using bind 8.2.1 as a forwarding dns in my localnet. now, my
dialup machine
> needs some time to get up, when a non local query comes in. bind times
out and
>  says domain not found. i enter it again, and it finds the domain...
> is it possible to set a timeout value ??
For a new timeout value you'll have to edit source and recompile bind.

I think you have dynamic IP and are running masquerading on your LAN.
But I think setting an other timeout value won't help, because the
triggering packet is UDP and goes to the default gateway in your LAN.
(wich doesn't probably doesen't exist in the Internet, if you have
a dynamic IP - masquerading does only rewrite TCP-addresses)
So the triggering UDP-packet with a wrong answer-address
(e.g. 192.168.0.1 = your gateway) is dropped by your ISP and is lost
forever - bind waits for answer on that packet until timeout.

Configure named.conf:
- comment out 'forward only' or 'forward first'
  (then the default configuration will bve used - I don't know what it
is)
- put in 'forwarders { 1.2.3.4; 1.2.3.5; };'  (Your forwarders...)

Then bind will look only at boot time for the forwarders (until timeout
and
disconnect). If you make a name-lookup (e.g. via Netscape) bind asks
the forwarders (and ipppd dials if it must) and you get an answer in
about 7sec (with ISDN autodial)
The trick: The triggering UDP-packed has correct answer-addresses,
so it isn't dropped by your ISP-gateway. (Normally no timeout)

Perhaps there are better solutions for that problem. Please tell me if
someone finds one. (or if some of my discriptions above are wrong)

Best regards,
Siegfried Hildebrand





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