[ale] Sendmail latency

[Ryan Fish]

> On Tue, 2005-01-25 at 09:53 -0500, Ryan Fish wrote:
> > > I am 99% convinvced that what you need is a local caching name server
on
> > > the mailserver.  Add it, then put 127.0.0.1 as your first nameserver
> > > in /etc/resolv.conf.
> >
> > - Is there any way to see if such a thing is already in place yet just
not
> > "on"?  Also, named.conf is used on the mail server and holds dns
information
> > for all of the domains hosted by this client.  Therefore, I still do not
> > feel good about renaming it and starting over with something new...
>
> One way to tell is whether you get results for
>
>   #host www.test.com 127.0.0.1

[root at mailserver mail]# host www.test.com 127.0.0.1
Using domain server:
Name: 127.0.0.1
Address: 127.0.0.1#53
Aliases:

www.test.com has address 208.48.34.132


>
> Another would be to check that "allow-recursion" is setup for 127.0.0.1
> in named.conf.  Finally look for the zone "*.*" in named.conf.

};
controls {
        inet 127.0.0.1 allow { localhost; } keys { rndckey; };
};
include  "/etc/rndc.key";
zone "." {
        type hint;
        file "named.ca";
};
zone "localhost" {
        allow-update { none; };
        type master;
        file "localhost.zone";
};
zone "0.0.127.in-addr.arpa" {
        allow-update { none; };
        type master;
        file "named.local";
};



>
> I would also verify that the "forwards" section of named.conf has the
> correct upstream nameservers identified.

I find nothing regarding "forwards" in named.conf


>
> > Another observation/question...  It appears as though sendmail is only
> > accepting a single connection as I never see more than one instance of
it
> > running at any one time.  I have worded, to a lesser degree, with mail
> > servers using sendmail in the past and am accustomed to seeing multiple
> > copies of sendmail listed when I do a "top" or "ps ax|grep mail".
Sendmail
> > should accept multiple connections by default so what, if anything,
would
> > keep it from doing so in 8.12.11-4?
>
> By most defaults, there will be 1 sendmail process to listen to port
> eth0 port 25, and 2nd process to handle /var/spool/clientmqueue/.
> Additionally sendmail will spawn processes (up until
> max_daemon_children) to handle queue delivery.  Is it possible that the
> senmail upgrade overwrote your previous sendmail.cf file?  Check the
> date on /etc/mail/sendmail.cf

- The sendmail processes must be working "right" then.
- sendmail.cf is dated 14JAN05 (I made a slight change to it that day per
something I found online.


>
> > The Java app in use is multi-threaded and therefore, uses at least 5
> > single-threaded agents at one time to send msgs to the mail server for
> > sendmail to handle.  However, at this time, only one of those agents is
> > allowed to be active at one time...
>
> That could be your problem.  Sendmail should allow simultaneous inbound
> connections (up to connection_rate_throttle).  Is the Java app doing a
> lot of dns lookups?  Is the Java app server DNS-resolvable from the
> sendmail box?

- I am not certain if the Java app is performing several DNS lookups as I
have to access to it.
- I can successfully 'host' the app server from the mail server (it is .220)
via forward dns but not reverse.

The client tried using the IP address of the mail server in their code and
found the same issue to exist.  Therefore it doesn't appear to be a reverse
DNS issue to me (at least at this point).