[afnog] Relay denied

[asseym at smartvisions.net]

Recently i started administering a server that has the ensim control panel
installed on it and uses the sendmail MTA for mailing. However this server
has persistent relay failures. Mail can be sent normally to any email
address that belongs to any domain that is also hosted on the same
machine.

However mail can not be sent to any account that is not hosted on the same
server using the desktop MUAs like outlook express, MS Outlook, Eudora
etc.

I have found out that mail can be sent easily and normally to any address
regardless of who hosts that domain with a flawless maillog. However when
mail is sent by the desktop MTAs the maillog developes errors like quoted
below---

-----------------------------------------<quote>
Jul  4 12:24:22 ensim sendmail[6204]: j649OJqt006204: ruleset=check_rcpt,
arg1=<asseym at yahoo.com>, relay=[193.108.254.83], re
ject=550 5.7.1 <asseym at yahoo.com>... Relaying denied. IP name lookup
failed [193.108.254.83]
Jul  4 12:24:23 ensim ipop3d[6205]: Login user=jahenda at smartvisions.net
host=[193.108.254.83] nmsgs=3/3
Jul  4 12:24:27 ensim sendmail[6204]: j649OJqt006204:
from=<jahenda at smartvisions.net>, size=0, class=0, nrcpts=0, proto=ESMTP
, daemon=MTA, relay=[193.108.254.83]
Jul  4 12:24:29 ensim sendmail[6204]: j649OJqu006204: ruleset=check_rcpt,
arg1=<jharnet at yahoo.com.au>, relay=[193.108.254.83]
, reject=550 5.7.1 <jharnet at yahoo.com.au>... Relaying denied. IP name
lookup failed [193.108.254.83]
Jul  4 12:24:32 ensim sendmail[6204]: j649OJqu006204:
from=<jahenda at smartvisions.net>, size=0, class=0, nrcpts=0, proto=ESMTP
, daemon=MTA, relay=[193.108.254.83]
</quote>-----------------------------------------------

Some MUAs return an error like "Relaying denied ---- Proper authentication
required"

others return one like ----

---------------------------------<quote>

Your message did not reach some or all of the intended recipients.

      Subject:	test
      Sent:	7/13/2005 9:13 PM

The following recipient(s) could not be reached:

      'asseym at cfi.co.ug' on 7/13/2005 9:13 PM
            550 5.7.1 <asseym at cfi.co.ug>... Relaying denied. IP name
lookup failed [193.108.254.83]

      'asseym at yahoo.com' on 7/13/2005 9:13 PM
            550 5.7.1 <asseym at yahoo.com>... Relaying denied. IP name
lookup failed [193.108.254.83]

------------------------------------</quote>

Iam really not so familiar with Sendmail and i would appreciate if anyone
points me in the right direction to solve this problem,

Thanks,
--assey.