Outlook and Messenger failures behind router 1

[ShunterAlhena]

Dear TekTips users,

I need help. I don't often say this but my knowledge stops here. We purchased a Planet router, using PPPoE DSL, with two computers. The ADSL connection sets up seemingly flawlessly, HTML pages downloaded etc.
However Outlook doesn't send mail. Sending has to be stopped, or Outlook restarted, or both. MSN Messenger doesn't send messages: re-logon required. If I don't use it for a while, re-logon is required again. My display picture is not sent at all. I have Kerio Personal Firewall (4.1.2 at the moment), full access allowed for both applications, and NOD32 Antivirus (2.12.3, full). Kerio's preset rules like ICMP blocking are on default.

I tried these methods:
-updating to latest router firmware (3.05)
-enabling/disabling HW firewall
-Port Forwarding (110 / 25 for Outlook)
-placing myself into DMZ
-enabling all kinds of pings in Kerio
-Setting MTUs the way written on this forum (in router and in XP as well)

Thanks for reading this, and Please help! These complaints may seem minor, but are most distressing when we have to reply quickly, or MSN refuses to work in the middle of a heated discussion

 

[bcastner]

I would bet on this being an MTU issue.
Test for your existing values:

http://www.dslreports.com/tweaks

 

[ShunterAlhena]

thanks, thanks and thanks!
It seems to have been the RWIN value: it was six times bigger than it is supposed to be. Problem seems to be solved. (Knock wood.)

BTW the MTU was incorrect as well.

 

[bcastner]

You are very welcome. I know how frustrating this can be.

Best Holiday wishes,
Bill Castner

 

[bcastner]

I should note that the status of you uPnP should be checked. Messenger is happiest if this is enabled.

More detail than you likely need:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wceupnps/html/ceconUPnPSecurity.asp

http://www.tomsnetworking.com/Sections-article21-page1.php

Just remember to enable uPnP on both the router, and at the client level through Control Panel, Add/Remove Programs, Add/Remove Windows Components, Network Services.

Steve Gibson has raised a lot of heat about uPnP being a security concern. I honestly do not agree. Certainly I disagree strongly with a workstation using current Hotfixes and Service Packs in Windows. And Messenger really wants it enabled. But you should know about the concerns and issues:

http://grc.com/UnPnP/UnPnP.htm