[ale] Sendmail latency

[Jim Popovitch]

--- Ryan Fish <FishR at bellsouth.net> wrote:

> > You are correct that sendmail (mail in general too) is heavily dependent
> > upon dns.  Ping alone doesn't necessarily test dns.  Can you 'host' each
> > machine name and ip successfully?
> 
> - When I 'host' the app server from the mail server I only receive
> 192.168.3.0

Hmmm, that should be a valid IP address (although .0 is probably usable),
something like 192.168.3.1.

> - When I 'host' the mail server from the app server I receive the full,
> proper IP address
> 
> > Make sure that the order is files,dns when you
> > "grep hosts /etc/resolv.conf"
> 
> - This results in no output on either server.  I know what you are looking
> for though but cannot remember the file to look in at this time...

Sorry, I meant /etc/nsswitch.conf
 
> > How many emails does the java applet send at once?  Are we talking
> > hundreds or thousands?
> 
> - Thousands.  When I spoke with the client around 8:30P EST tonight there
> were 7500 msgs in the queue used by the Java app on the App server.
> Typically that queue is cleared almost instantly.

It could be that the sendmail queue is getting backlogged due to latency at
other (receiving) mail servers.  List would be indicated in the "stat" output
of each connection attempt in /var/log/maillog.   Check also for any errors in
/var/log/maillog indicating connection limiting due to high load average? 

-Jim P.