Yahoo! mail error when sending email w/ attachment

[justanotherdayintheoffice]

Hi all,

Well, we are experiencing this:

"Connection Error: DCID: 67603 domain: yahoo.com IP: xxx.xxx.xxx.xxx port: 25 details: EOF interface: xxx.xxx.xxx.xxx reason: network error

Info: Delayed: DCID 67603 MID 81226 to RID 0 - 4.4.2 - Bad connection ('000', ['Connection Lost']) []

This happens whenever we send an email to yahoo domain with an attachment greater than 4mb.

All emails without attachment is successfully sent to a yahoo email address.

Sometimes, emails with attachment less than 3mb is sent after many retries.

I have tried domain mail and domain debug logs and found no error on it.

All emails to other domains with or without attachment is always sent successfully.

[Christopher Smith]

Hi,

It sounds as if you have already done a fair amount of analysis into this issue.  From what you have provided thus far it appears there are two specific constants

1) It only effects messages outbound to yahoo

2) the messages are larger than 4mb.

Currently I do not believe that yahoo has a global 4mb limit on inbound traffic however it is possible this could occur for a specific sending IP.

While it is possible to limit the file size outbound to a specific destination on the appliance , we would typically see a different type of message in the logs. I would be interested in seeing the full text of the domain debug logs if you have them.

The errors you provided seem to indicate a network related issue. Are there other errors of this type in the mail logs that do not involve yahoo?

Is it possible that there is a firewall or ACL that has a specific rule to limit the outbound message/file size to this destination?

If the debug logs do not provide enough data you may want to consider doing a packet capture.

Christopher C Smith

CSE

Cisco IronPort Customer Support

[justanotherdayintheoffice]

Hi Chris,

I already have the following:

1. mail logs

2. domain debug logs

3. tcpdump.

While the mail logs and tcp dumps are small in size, the domain debug log is quite heavy as it contains a 5mb attachment with it.

I again did some test send with a 5mb attachment and to my surprise it was successfully sent immediately. and then on my second try that day, I encountered the same error again.

Can I ask you to take a look at the logs?

Thanks

-karl

[jgandla]

Greetings Karl,

Does the issue still persist? If yes, can you please open a support case, and we will be able to take a look at the logs to investigate further?

Thanks,

------------------------------------------------

Jyothi Gandla

Customer Support Engineer

Cisco IronPort Customer Support

.:|:.:|:.

c i s c o