Mailscanner and DNS

John Rudd jrudd at ucsc.edu
Thu Sep 28 00:04:06 IST 2006


Logan Shaw wrote:
> 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.
> 
> Maybe:
> 
> 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.
> 

That was one of the things I had been worrying about.


But, I think that gets reset on every slave cull/respawn that MS does.


ANd, for anyone who was waiting for the answer:  I had my subordinate 
restart sendmail on our mail servers, and everything is quiet on the 
campus name servers now.  We're just hitting our own name servers.


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