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cannot receive email from (some) servers

i have SG TCP optimized my server

and now it seems to be all OK

 

thank you

<P>i have SG TCP optimized my server</P> <P>and now it seems to be all OK </P> <P mce_keep="true"> </P> <P>thank you</P>

i have same problem like described in this (very old) post

 

http://www.webservertalk.com/message1018435.html

 i get email from gmx, ebay, and so on

 

but not from hotmail, my server a work ..

 

any idea

 

<P>i have same problem like described in this (very old) post</P> <P mce_keep="true"> </P> <P><A href="http://www.webservertalk.com/message1018435.html">http://www.webservertalk.com/message1018435.html</A></P> <P> i get email from gmx, ebay, and so on</P> <P mce_keep="true"> </P> <P>but not from hotmail, my server a work ..</P> <P mce_keep="true"> </P> <P>any idea</P> <P mce_keep="true"> </P>

[quote user="ral"]

i have same problem like described in this (very old) post

 

http://www.webservertalk.com/message1018435.html

 i get email from gmx, ebay, and so on


but not from hotmail, my server a work ..
 

any idea

[/quote]

 

Firewall or packet fragmentation comes to mind.  If there is nothing between Mercury/32 and the server  like some sort of anti-spam/virus application then I think you should look at packet fragmentation.  POP3/SMTP transmissions may fail if the MTU packet size is so large that a packet is fragmented.  In many cases the receiving system router blocks the receiving servers "packets fragmented" response to the sending system using "MTU Discovery".  These oversize packets are not accepted and so are resent.  This results in a timeout, generally at the end of the message transmission but it can be anywhere in the process.  You need to reduce the MTU size. Windows defaults to a 1500 MTU and many routers and DSL connections need 1492.  You might simply want to turn off the MTU Discovery operation.

You might want to get a copy of SG TCP Optimizer that I find quite handy.  http://www.speedguide.net/downloads.php  This little utility will allow you to test your MTU for maximum size without fragmentation against specific servers.  If will also make it easy to adjust the MTU. 

And finally, does this computer, by chance, happen to have an NVidia NForce 4 chipset on the motherboard?  If so, many other have had this exact problem, and it turned out to be an optimization setting for the built in NIC which caused the problems with packet fragmentation. Disabling the advanced optimization capability called "checksum offload" made all the problems of sending SMTP mail via WinPMail disappear.


[quote user="ral"]<p>i have same problem like described in this (very old) post</p> <p mce_keep="true"> </p> <p><a href="http://www.webservertalk.com/message1018435.html" mce_href="http://www.webservertalk.com/message1018435.html">http://www.webservertalk.com/message1018435.html</a></p> <p> i get email from gmx, ebay, and so on</p> <p mce_keep="true"> </p> <p mce_keep="true">but not from hotmail, my server a work ..  </p> <p>any idea</p><p> [/quote]</p><p> </p><p>Firewall or packet fragmentation comes to mind.  If there is nothing between Mercury/32 and the server  like some sort of anti-spam/virus application then I think you should look at packet fragmentation.  POP3/SMTP transmissions may fail if the MTU packet size is so large that a packet is fragmented.  In many cases the receiving system router blocks the receiving servers "packets fragmented" response to the sending system using "MTU Discovery".  These oversize packets are not accepted and so are resent.  This results in a timeout, generally at the end of the message transmission but it can be anywhere in the process.  You need to reduce the MTU size. Windows defaults to a 1500 MTU and many routers and DSL connections need 1492.  You might simply want to turn off the MTU Discovery operation. You might want to get a copy of SG TCP Optimizer that I find quite handy.  http://www.speedguide.net/downloads.php  This little utility will allow you to test your MTU for maximum size without fragmentation against specific servers.  If will also make it easy to adjust the MTU.  And finally, does this computer, by chance, happen to have an NVidia NForce 4 chipset on the motherboard?  If so, many other have had this exact problem, and it turned out to be an optimization setting for the built in NIC which caused the problems with packet fragmentation. Disabling the advanced optimization capability called "checksum offload" made all the problems of sending SMTP mail via WinPMail disappear. </p>
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