Unwanted ISDN connections caused by BIND

Bernd Pörner poerner at darmstadt.gmd.de
Thu Aug 12 10:45:58 UTC 1999


First, thank you for your fast response.

Jim Reid wrote:

> This is to be expected. Your name server has to talk to other name
> servers, especially if it has to resolve external names. What you
> could do is configure your PPP/ISDN code to only let DNS traffic out
> if the serial line is already up. [OTOH, that might stop external
> lookups from working, zone transfers might fail, valid zones could
> expire, etc, etc.] Another approach would be to keep the line up for
> one PPT-charging-unit after the DNS lookup in the hope that someone
> generates some off-site traffic - web access or whatever - soon after
> they'd looked up the external name.
>
> You might also want to take a look at the dialup option in
> BIND8.2.1. It won't stop your name server sending queries to external
> name servers. [Probably nothing can.] However it might help minimise
> the amount of ISDN traffic that the name server generates.

O.K. I took a closer look to my log files and found out that with nearly all those
"automatic" and unwanted ISDN connections BIND is calling the root DNS servers:

   * 192.203.230.10 (E.ROOT-SERVERS.NET)
   * 202.12.27.33 (m.root-servers.net)
   * 128.8.10.90 (d.root-servers.net)
   * ...

Can you give me a tip, why BIND makes DNS queries to the root DNS servers at night,
when no other process is running, which makes any query to BIND?
In the meantime I configured sendmail in a way that it is inactive at night. So the DNS
queries couldn't be produced by sendmail. Our client PCs are switched off at night, so
I suspect, that BIND makes these queries by itself; maybe to update the "root.hint"
file?

Bernd




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