Unable to connect to email servers

[thrashcat]

I have a unique problem,
A customer called me into thier office to troubleshoot thier email problem,
none of thier client computers can connect to the email providers POP or
SMTP servers. Also, the internet connections and network drives connection
are intermitent. Here is the run down,
1. the email server is located @ mail.cbmtpa.com
2. I can Ping this mail server from the internal network from machines that
have NOT been set up with email.
3. If I set up an email account on a fresh machine I can send and recieve
the emails from the server 1 time.(second attempt throws error.)
(Did not include error code because from a test from a remote site gives
a different #)
4. Tested from remote site: on a fresh loaded machine with the same
results.( 1 time connectivity) The 1 time connectivity was through the ISP's
Web Interface and it broke the Outlook (Default) accounts ability to connect
which was to POP.pacbell.yahoo.com.
5. Virus, Hijackthis and spyware scan AdAware and Ewido, Found nothing.
6. At present No NAT stacks are anything unusual either.
7. Thinking it must be some kind of WORM that is not yet Identified by
aVast, OfficeScan, Notrtons Enterprise or AVG as all of these test NEGATIVE.
8. Contacted ISP (Mpower) and a test of the T1 line back to the router comes
up Negative.
9. Contacted Email provider (Ipower) with same results.

Office setup consists of:
T1 from MPower
Linksys 8port Rackmount Router
1 Server handling PCAnywhere remote access (Server2000)
1 Server handling Routing internal dns,active dir ect.(Server2003) Domain
Controller.
1 server handling file sharing (server2003) This server I did find an
invalid DNS setting for, It was searching for itself.) Replication Partner
14 Client computers logging on to domain

If anyone has any sugestions or has ever encountered this PLEASE HELP!!!!!
I have tried the fix microsoft has suggested by regedt32
HKCU/Software/Microsoft/Protected Storage System Provider/(subkey delete) to
no avail.
System keeps asking for password and will no longer PING the mail server
(reports host is unreachable.
P.S. I tried this with BOTH firewall ports 110 & 25 OPEN and CLOSED wuth the
same results.

 

[Brian Tillman]

Office setup consists of:
T1 from MPower
Linksys 8port Rackmount Router

Check the MTU settings in the router. Try setting it at 1498 or lower.

 

[thrashcat]

I tried resetting the MTU to 1498 then 1494 then 1490 with no change,
The problem seems to stem from Outlook, Both Outlook2000 & 2003 have the
same problem as does Outlook Express. Seems to me that the Password is not
being sent weather it be automatic or manual imput. Tried Shutting down the
fire wall and the result is still the same.

Any other suggetions? and thanks for your reply Brian.....

 

[Brian Tillman]

I tried resetting the MTU to 1498 then 1494 then 1490 with no change,
The problem seems to stem from Outlook, Both Outlook2000 & 2003 have
the same problem as does Outlook Express. Seems to me that the
Password is not being sent weather it be automatic or manual imput.
Tried Shutting down the fire wall and the result is still the same.

Since all of the mail clients have the problem, it's definitely not an
Outlook issue. Have you tried enabling diagnostic logging, either in
Outlook or in Outlook Express to see what may be happening between the
client and the server?

 

[thrashcat]

For future Reference:
If any one has this problem and you are dealing with ISP MPower,
There DNS Servers suck...This is what was causing the problen....
I pointed the DNS Servers to an alternate and the problem went away.....
Thanks for your imput.