Re: [cobalt-users] re: SMTP claims to be down but isn't

[Jeff Lasman <blists@xxxxxxxxxxxxx>]

On Tuesday 13 April 2004 11:40 am, John MacDonald wrote:

> This seems to work however the query time
> is very inconsistent - ranging from 130ms to
> 850 ms...and once I even recieved a timeout.
> Do you think that the delay/error message
> could be related to the fact that my Raq
> does not host its own DNS? (We're using
> our ISP's because we are not hosting any
> sites on this machine - its for mail only).

It would have nothing to do with you not hosting DNS; it could have 
something to do with you not having valid reverse DNS.

> I'm also curious as to why my firewall
> doesn't show any DNS requests to the
> blacklist hosts servers?...only UDP/53
> requests I see open in the firewall
> sessions are those to the DNS of our
> ISP - Does this server relay the
> lookup request to the blacklist host
> and then return it to us?

Yes, when you do a dig, you're asking the server set up in your 
/etc/resolv.conf file; it doesn't know it's looking for a spamcop 
server (and in fact the spamcop servers are NOT at bl.spamcop.net).

All it knows is that it must look up 229.240.58.65.bl.spamcop.net; it 
does it the same way it looks up any DNS request; if it doesn't have it 
in it's cache, it asks the root servers, and goes from there.

To check the spamcop dns server directly you'd have to know it's name.

If you do, let me know, and I'll tell you how to format the query.

Jeff
-- 
Jeff Lasman, nobaloney.net, P. O. Box 52672, Riverside, CA  92517 US
Professional Internet Services & Support / Consulting / Colocation
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