[BlueOnyx:13504] Re: EMail clogging up - DNS?

[Chris Gebhardt - VIRTBIZ Internet]

On 8/9/2013 11:22 AM, Jim Matysek wrote:
> We've had this happen every now and then, particularly during heavy
> usage times on the server.
>
> Running 5106R on an Aventurin{e} VPS. What happens is that email sent to
> our hosted domains gets stuck in /var/spool/mqueue and not delivered. We
> can get thousands of messages stuck there in the course of several
> hours. When I shell into the machine and try an nslookup usms.org (our
> main domain), I get a timeout saying ";; connection timed out; no
> servers could be reached". So it appears that is the reason why the mail
> isn't getting through - it can't find the domain that is hosted on this
> server.
>
> I've tried restarting DNS through the gui or via the command line using
> named restart to no avail. I've tried restarting sendmail via the shell.
> Nothing I try seems to un-stick this except re-booting that VPS.
> HOWEVER, if I notice the problem late at night I can just let it go and
> one of the automated nightly server tasks will un-stick it. Does anyone
> have any ideas what it is that may be working overnight that I can try
> via the command line? Re-booting is too big a hammer to hit it with
> during the day when we have important activities going on that we don't
> want to interrupt.

Hi Jim,
It seems pretty clear this is a DNS failure.   So if you fix the DNS 
issue, this should fix that problem.

Are you using the DNS servers provided by your ISP?   Are they 
responsive if you query them from the VPS?

Once you're certain that your DNS issue is solved, if you want to 
immediately process the queue, then you can issue this:
sendmail -q -v

That will step through each message and attempt delivery.

-- 
Chris Gebhardt
VIRTBIZ Internet Services
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