Root mail queue'd but not forwarded

[Jeff Boyce]

Greetings -

I manage a small office network with one RHEL 3 update 9 file server and
about a dozen windows clients.  Recently my system monitoring emails that 
are sent
to root (and aliased to my email address) are not being forwarded, but are
being held in the sendmail queue.  This had been working correctly without a
problem on my server for about four years.  My objective is to get root's 
emails directed to my normal user email account.

This problem appeared
immediately after I replaced a network switch that had failed.  The old
switch was a Dell Power Connect 2016 and the new switch is a Dell Power
Connect 2724.  The new switch was installed using the unmanaged
configuration.  The replacement of this switch is the only change (hardware
or software) to my system in over a year, so I am inclined to think that it
may be part of the problem.  I am guessing that I have a bad configuration
in my network or sendmail system, and replacing the switch caused the
problem configuration to appear.  But then again I am a fairly novice linux
administrator and could be completely wrong.  I have done a lot of googling
to try and learn what I might have wrong in my configuration but have not
been able to figure it out.  I am hoping that a more experienced admin can
give me some advice on how to further diagnose my problem, or point me in
the right direction.  Sorry for the long post, but I know how difficult it
is to diagnose a problem without complete information.

/etc/aliases includes the following
# Person who should get root's mail
root: jboyce at meridianenv.com

Here is what I see in the Sendmail Queue through Webmin for a single email
that is queue'd.

>From root <root at bison> To root at bison Date Sun, 15 Feb 2009 04:02:03 -0800
Subject LogWatch for bison
################### LogWatch 5.2.2 (06/23/04) ####################
       Processing Initiated: Sun Feb 15 04:02:03 2009
       Date Range Processed: yesterday
     Detail Level of Output: 0
          Logfiles for Host: bison
 ################################################################
 --------------------- sendmail Begin ------------------------ 
Bytes Transferred: 24709
Messages Sent:     4
Total recipients:  4
2 messages returned after 4 hours
6 messages returned after 5 days
 ---------------------- sendmail End ------------------------- 
------------------ Disk Space --------------------
/dev/sda7             2.0G  1.5G  381M  81% /
/dev/sda3             190M   54M  127M  30% /boot
/dev/sda8            1012M   33M  928M   4% /tmp
/dev/sda5             9.7G  2.8G  6.4G  31% /usr
/dev/sda6             9.7G  2.9G  6.3G  32% /var
/dev/sda2             2.5G  2.0G  443M  82% /home
/dev/sda10             40G   33G  5.0G  87% /ecosystem
 ###################### LogWatch End #########################


>From Mail Delivery Subsystem <MAILER-DAEMON> To <root at bison> Date Sun, 15
Feb 2009 09:01:45 -0800 Subject Warning: could not send message for past 4
hours
    **********************************************
    **      THIS IS A WARNING MESSAGE ONLY      **
    **  YOU DO NOT NEED TO RESEND YOUR MESSAGE  **
    **********************************************
The original message was received at Sun, 15 Feb 2009 04:02:40 -0800
from localhost.localdomain [127.0.0.1]

   ----- Transcript of session follows -----
451 bison: Name server timeout
451 bison: Name server timeout
451 bison: Name server timeout
Warning: message still undelivered after 4 hours
Will keep trying until message is 5 days old
451 bison: Name server timeout


>From Mail Delivery Subsystem <MAILER-DAEMON> To postmaster Date Fri, 20 Feb
2009 11:15:21 -0800 Subject Postmaster notify: see transcript for details
The original message was received at Sun, 15 Feb 2009 09:01:45 -0800
from localhost with id n1FGwSJ7008534

   ----- The following addresses had permanent fatal errors -----
<root at bison>

   ----- Transcript of session follows -----
451 bison: Name server timeout
Message could not be delivered for 5 days
Message will be deleted from queue


These indicate to me that I might have a problem in my network configuration
or host file.  So here is what that looks like.

/etc/hosts
# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1 localhost.localdomain localhost
192.168.112.1 Bison Bison
192.168.112.2 Bison2 Bison2

/etc/sysconfig/networking/devices/ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
IPADDR=192.168.112.1
NETMASK=255.255.255.0
GATEWAY=192.168.112.10
TYPE=Ethernet
USERCTL=no
PEERDNS=no

My second nic (x.x.x.2, bison2) is not connected to the network and was just
setup as a standby nic in case there was a problem with the primary nic.  I 
have also tried my hosts file with Bison as all lower case without any 
difference.  While googling I saw reference to needing a period at the end 
of my host name in the hosts file since I do not use a fully qualified 
domain name, but that made no difference either.  The address 192.168.112.10 
is my DSL router.

/etc/host.conf
order hosts,bind

Both named and sendmail are started at boot time, although I don't recall 
that I have ever changed the stock configuration for either named or 
sendmail.  My system had been up for 450+ days, but rebooted it a few days 
ago with no change in this problem.

/etc/resolv.conf
nameserver 192.168.112.10
nameserver 4.2.2.2


I am not sure of what other configuration files might be of interest in 
helping diagnose this problem.  Sendmail is only used for the root system 
emails and is not used for our company email system.  Thanks for any 
guidance that can be provided.  I have been scratching my head over this one 
for about a month.

Jeff Boyce
www.meridianenv.com