Sentech and email sending weirdness

[brendonhatcher]

Hi all. I am looking for some advice...

1. Bought a new notebook running Windows XP Home SP2

2. Linked to old style Sentech modem as follows:

PC --> Ethernet --> switch --> Windows 2000 pc --> usb --> modem

3. Outlook configured to send via authenticated smtp on my hosted server (NOT sentech smtp server)

Very small messages in any format are sent.
As soon as I add an attachment or even a tiny embedded image (HTML format), I can't sent.

Send error is

Here's the weirdness:

1. I can send the same messages without error if I bypass Sentech using a dialup account
2. If I send from the PC that is directly connected to the modem, no problem
3. If I attach the modem directly to my notebook, no problem

What I have tried so far

I can ping and telnet to the smtp server.
I have reinstalled Outlook and all account settings
I have disabled and then uninstalled my anti-virus
I have updated Office to SP3
I have adjusted the MTU on my LAN card
I have increased the timeouts on my server connection
I have tried sentechs SMTP server

So far I have spent two full days at troubleshooting. Any input would be greatly appreciated.

Brendon

 

[brendonhatcher]

Additional info

Forgot to post the error message!

Task 'server name - Sending and Receiving' reported error (0x800ccc0f): 'The connection to the server was interrupted. If this problem continues, contact your server administrator or Internet service provider (ISP).

Additional data:

I can receive messages

I suspect that Sentech is capturing my smtp transfer, routing it through their smtp server, and that the problem is occuring there.

The evidence:
when I review the email header of a message that I sent to myself, the originating IP address is 196.31.34.xxx, not that of my SMTP server.

 

[bekdik]

SMTP servers always route amongst themselves as this is the way SMTP works. I would guess that the attachment size is exceeding that allowed by a server. Are your attachments larger than 2MB? If so, split them up into smaller chunks.

 

[brettwlewis]

I see the 0x800ccc0f error all the time in Outlook, from one or two of my seven acounts, each time I do a send and recieve. And not the same one's each time - there is no pattern.

I thought it was my antivirus proxy maybe not being able to handle the number of accounts, but I get the error when I kill my AV too.

I don't think its a send issue though. I send mail via an internal SMTP server and don't have issues there.

Personally, I have a feeling its Sentech's latency causing connection timeouts between your PC and your POP server.

But I've tried, to no avail, to get them to improve their latency. In fact, its the main reason that I'll be moving to ADSL as soon as Telkom comes to the party.