Recent problem sending mails with attachments

O

obound

Guppy
This issue is specific to one mail account. I have been using the same server (mail3) for this account for a year or so. For the last week or so, I'm unable to send mails with attachments. While mails without attachments go through fine. If the total size of attachments exceeds about 60K then the mail does not get sent.

I use ThunderBird as my mail client and TB indicates that it is delivering the mail. The delivery percentage starts moving up for about 15 seconds or so. Then all of a sudden there is no traffic going through. This happanes when somewhere around 60K to 80K of the mail has gone through. After half a minute or so, I get an error saying that the smtp server is unavailable or not accepting conenctions.

I have tried even after creating a new profile in Thunderbird and the same error occurs.

I need to know if there is any smtp log at the erver which can be analysed to get a clue about the cause of this error. The smtp session log generated by ThunderBird doesn't help much.
 
I have found out the real cause of the problem today. My ISP was throttling the smtp port (both 25 and 587). It was not as if it was being blocked as I could send normal mails. But when sending mails with attachments, the communication with Jodo smtp server was abruptly terminated. So my mail client reported an error in communicating with the smtp server. My smtp logs signified the same as well.

After exhausting all options, I tried conencting through another ISP and the problem vanished. Then I contacted my primary ISP (Airtel, Chennai, India) and came to know, after much prodding, that they have introduced some new policies since May 1.

On the bright side, they have set up a relay server and provided me with an account through which I can send mails using my Jodo mail identities.

At the end of all this, I have upgraded my mail client (Thunderbird 2) and cleaned up my system. Jodo's smtp servers will benefit by getting rid of my send mail load as well.

Can anyone tell me how an ISP can do this? Not the ethical / moral part but the techical part. Is this a normal / prevalent practice elsewhere?
 
Hello obound,

It is getting quite common for them to do portblocking, due to spammers using home machines to send loads of spam thru trojans and smtpserver enabled virii/malware.
 
You must log in or register to reply here.
Back
Top