Mailscanner and DNS

Logan Shaw lshaw at
Wed Sep 27 23:43:12 IST 2006

On Tue, 26 Sep 2006, John Rudd wrote:
> Does MailScanner cache resolver information and then do lookups directly?
> Specifically, if I change the DNS server information in resolv.conf, do I 
> need to restart MailScanner?
> We've taken certain name servers out of our resolv.conf, and yet we're still 
> seeing traffic to those servers from our MailScanner machines.


1.  MailScanner uses SpamAssassin.
2.  SpamAssassin uses the Net::DNS:Resolver Perl module.
3.  Net::DNS::Resolver uses Net::DNS::Resolver::UNIX on
     Unix systems.
4.  Net::DNS::Resolver::UNIX reads /etc/resolv.conf directly
     and doesn't call libc or anything like that, I believe.

I'm not positive what Net::DNS::Resolver::UNIX does, but if
it only checks /etc/resolv.conf at startup, that could be
the problem.

   - Logan

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