Posts Tagged ‘smtp’

SMTP timeout after sending data block… What’s The Issue?

Thursday, September 13th, 2012

This type of mail server to mail server SMTP failure is usually accompanied by log message like the following:

“SMTP timeout while connected to xx.xx.xx.xx [xx.xx.xx.xx] after sending data block (8189 bytes written): Connection timed out”

This type of failure could arise from any number of network connection issues, firewall packet inspection, a security application, or a virus scanner on the local mail server.  However, in every case we have encountered this it has been due to an issue with security systems on the receiving system, typically on the router itself.  For the most part, this failure only occurs when the recipient’s scanning system is processing emails with attachments (regardless of size) and it reaches a point where it fails/freezes.  After that, the recipient system stops accepting new SMTP data and after a predetermined time, the SMTP connection then times out.
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Currently not permitted to relay through this server – Worst Rejection Ever!

Wednesday, July 28th, 2010

Of all the confusing and convoluted mail server rejections commonly in use, “Currently not permitted to relay through this server” causes more Support tickets for us than any other.  Worse yet, it’s not even an error that we use, so we find ourselves constantly trying to coherently explain what someone else’s mail server is saying.

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Can Anyone Send Emails Claiming To Be From Me?

Friday, January 29th, 2010

The short answer is yes. Anyone can forge the sender (From) field of an email and have it claim to be coming from pretty much any address they want.

At first glance you might think “That’s horrible, why do we allow that to happen?”  The truth is that it’s rather common, and you might even do this yourself, though for entirely innocent reasons.

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A Quick Look At How Email Works

Friday, January 8th, 2010

Understanding the basics of how email works can make life a lot easier for any email user. Especially those who are interested in using email effectively.  In this post we’ll cover the basics that every user should know.

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