Unwanted ISDN connections caused by BIND

[Bernd Pörner]

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 Pörner wrote:

> We have a linux box acting as DNS, mail and proxy server. We are
> connected to our provider via an ISDN line. Our BIND version is
> 8.1.2-22.
>
> Every time the machine boots it makes an unwanted ISDN connection to the
> provider, exactly in the moment when BIND starts. Also later, in
> irregular intervals, the machine makes unwanted ISDN connection. I ran
> "isdnctrl verbose 3" to find out which process makes these connections.
> They are made via UDP protocol over port 53 (which is BIND's port).
>
> Another curious thing:
> If BIND is started during boot-up, sendmail is unable to start during
> boot-up. After boot process is over I can start sendmail
> ("/sbin/init.d/sendmail start") without problems.
> If BIND isn't started during boot-up, sendmail can be started without
> problems during boot-up.