Hi,

We had sendmail working fine on our RedHat ES 3 server for close to 2
years. Over one weekend sendmail stopped working. No server files were
changed on this weekend.

We have instigated a work around by modifying the sendmail.mc file to
use actual IP addresses instead of the domain name of the mail server.
We are at a lost as to what caused this and why the modifications we
have since made were required.

We have a hosts file that contains:
202.xx.xx.xx mailrelay.hosting.blah.com

I've included the original sendmail.mc file that worked for the last 2
years and the modified sendmail.mc file that was recently modified to
get it working.

Sendmail version being used:
sendmail-devel-8.12.11-4.RHEL3.6
sendmail-doc-8.12.11-4.RHEL3.5
sendmail-cf-8.12.11-4.RHEL3.6
sendmail-8.12.11-4.RHEL3.6

The maillog contains entries like the following on failed messages:
Jan 15 03:11:58 icadsweb sendmail[544]: l0ED12Gw030942:
to=<support@4loop.com.au>, delay=03:10:56, xdelay=00:01:20,
mailer=smtp, pri=408278,
relay=mailrelay.hosting.blah.com, dsn=4.0.0, stat=Deferred: Name
server: mailrelay.hosting.blah.com: host name lookup failure

Our working sendmail.mc file:
dnl divert(-1)
include(`/usr/share/sendmail-cf/m4/cf.m4')
VERSIONID(`linux')dnl
OSTYPE(`linux')dnl
dnl
define(`RELAY_HOST', smtp:[xxx.xxx.xx.xx])
define(`SMART_HOST', smtp:[xxx.xxx.xx.xx])
define(`confDONT_PROBE_INTERFACES',true)dnl
define(`PROCMAIL_MAILER_PATH',`/usr/bin/procmail')dnl
define(`ALIAS_FILE', `/etc/aliases')dnl
dnl
FEATURE(always_add_domain)dnl
FEATURE(redirect)dnl
FEATURE(nocanonify)dnl
FEATURE(nocanonify)dnl
FEATURE(`smrsh',`/usr/sbin/smrsh')dnl
FEATURE(`mailertable',`hash -o /etc/mail/mailertable.db')dnl
FEATURE(`virtusertable',`hash -o /etc/mail/virtusertable.db')dnl
FEATURE(always_add_domain)dnl
FEATURE(use_cw_file)dnl
FEATURE(use_ct_file)dnl
FEATURE(local_procmail,`',`procmail -t -Y -a $h -d $u')dnl
FEATURE(`access_db',`hash -T<TMPF> -o /etc/mail/access.db')dnl
FEATURE(`accept_unresolvable_domains')dnl
FEATURE(masquerade_envelope)dnl
FEATURE(masquerade_entire_domain)dnl
dnl
MASQUERADE_AS(`icadspost.com.au')dnl
MASQUERADE_DOMAIN(`icadspost.com.au')dnl
MAILER(smtp)dnl
MAILER(procmail)dnl

Our non-working sendmail.mc:
dnl divert(-1)
include(`/usr/share/sendmail-cf/m4/cf.m4')
VERSIONID(`linux')dnl
OSTYPE(`linux')dnl
dnl
define(`RELAY_HOST', smtp:[mailrelay.hosting.blah.com])
define(`SMART_HOST', smtp:[mailrelay.hosting.blah.com])
define(`confDONT_PROBE_INTERFACES',true)dnl
define(`PROCMAIL_MAILER_PATH',`/usr/bin/procmail')dnl
define(`ALIAS_FILE', `/etc/aliases')dnl
dnl
FEATURE(always_add_domain)dnl
FEATURE(redirect)dnl
FEATURE(nocanonify)dnl
FEATURE(nocanonify)dnl
FEATURE(`smrsh',`/usr/sbin/smrsh')dnl
FEATURE(`mailertable',`hash -o /etc/mail/mailertable.db')dnl
FEATURE(`virtusertable',`hash -o /etc/mail/virtusertable.db')dnl
FEATURE(always_add_domain)dnl
FEATURE(use_cw_file)dnl
FEATURE(use_ct_file)dnl
FEATURE(local_procmail,`',`procmail -t -Y -a $h -d $u')dnl
FEATURE(`access_db',`hash -T<TMPF> -o /etc/mail/access.db')dnl
FEATURE(`accept_unresolvable_domains')dnl
FEATURE(masquerade_envelope)dnl
FEATURE(masquerade_entire_domain)dnl
dnl
MASQUERADE_AS(`icadspost.com.au')dnl
MASQUERADE_DOMAIN(`icadspost.com.au')dnl
MAILER(smtp)dnl
MAILER(procmail)dnl

Any in the above would be appreciated

Kind Regards
Trevor

telerover wrote:
> Hi,
>
> We had sendmail working fine on our RedHat ES 3 server for close to 2
> years. Over one weekend sendmail stopped working. No server files were
> changed on this weekend.

Odds are your system never actually used the hosts file and/or it was
incorrect.
Check your /etc/nssswitch.conf

What happened could be that DNS either changed or broke.

Test the DNS resolution on the box.

Ping the name.

Then run sendmail on the command line as -bs or -q or direct email with
DNS debugging such as with -d8.20

Hi

Thanks for the response.

what do i check the nssswitch file for exactly? Is there something i
should be looking for in particular?

Thanks

On Jan 17, 11:31 am, "jmai...@ttec.com" <jmai...@ttec.com> wrote:
> telerover wrote:
> > Hi,
>
> > We had sendmail working fine on our RedHat ES 3 server for close to 2
> > years. Over one weekend sendmail stopped working. No server files were
> > changed on this weekend.Odds are your system never actually used the hosts file and/or it was
> incorrect.
> Check your /etc/nssswitch.conf
>
> What happened could be that DNS either changed or broke.
>
> Test the DNS resolution on the box.
>
> Ping the name.
>
> Then run sendmail on the command line as -bs or -q or direct email with
> DNS debugging such as with -d8.20

On Wed, 24 Jan 2007 19:16:38 -0800, telerover wrote:

My /etc/nsswitch.conf file has the following entry:

hosts: files dns

This says to use /etc/hosts first and then use DNS when attempting to
resolve a host name.

On Wed, 24 Jan 2007
19:16:38 -0800, telerover wrote:

> Hi
>
> Thanks for the response.
> what do i check the nssswitch file for exactly? Is there something i
> should be looking for in particular?
>
> Thanks
>
> On Jan 17, 11:31 am, "jmai...@ttec.com" <jmai...@ttec.com> wrote:
>> telerover wrote:
>> > Hi,
>>
>> > We had sendmail working fine on our RedHat ES 3 server for close to 2
>> > years. Over one weekend sendmail stopped working. No server files were
>> > changed on this weekend.Odds are your system never actually used the hosts file and/or it was
>> incorrect.
>> Check your /etc/nssswitch.conf
>>
>> What happened could be that DNS either changed or broke.
>>
>> Test the DNS resolution on the box.
>>
>> Ping the name.
>>
>> Then run sendmail on the command line as -bs or -q or direct email with
>> DNS debugging such as with -d8.20