Email delivery error.

[#1]

I am suddenly (in the last two weeks) having emails bounced back after a long time (about five days) from someone I email regularly. They have asked me to check that there is not a problem with the PN email server as well as them checking. The error message is..

A message that you sent to the following recipient could not be delivered due to a permanent error. ** The remote server 85.159.**.** responded with: ** support@****.co.uk 420:Connection failed This message was created automatically by mail delivery software on the server avasout01.

I think I am correct in saying thet avasout01 is a PN server. As far as I can see the fault is at their end. All the avasout01 does is generate the error message. Could one of the Techs please check what exactly the 420 error means?

Thanks.

[#2]

The plot thickens!

The email recipients IP provider uses a Barracuda Networks Firewall. They are saying that my email address is being blocked "on reputation of ISP", which bothers me a little! 

However, we have just discovered that changing my smtp port from the default 587 to 25 allows emails to be received properly. So what's that all about? 

Any techs any ideas?

[#3]

Just guessing, but has it worked with the amended port because it used a different avasout(n) to send it? Nothing directly to do with changing the connection port.

[#4]

@spraxyt

But using port 587 consistently fails, they say to a firewall rejection at their end on "bad reputation". Port 25 is fine. Same email address.

[#5]

@nozzer but does use of Port 25 also result in messages being relayed through avasout01? I suspect not.

[#6]

Ah, I see what you mean. I think you might be right because the bounces I have had have all referred to avasout01. I have relayed this info through the chat facility and someone will apparently look at it.

[#7]

It doesn't look as though my chat with support yesterday has managed to raise a ticket for this. It appears that Barracuda Networks firewall has Plusnet down as a "bad reputation", but only if emails are sent vis port 587 through avasout01. Rather than going through all the rigmarole of explaining on the phone again could someone please have a look at this.

It seems to me that their third party firewall is expecting something different from avasout01 from what it's actually getting, which points to some sort of configuration problem with that smtp server.

[#8]

It would be odd for avasout01 to be configured differently from the other avasoutnn servers in the family. In my view if the recipients reset the reputation of avasout01 on their system faster progress would be made.

In the unlikely event that avasout01 is still originating questionable content it will quickly end up blocked again.

[#9]

Unfortunately they aren't really interested. All they are saying is that if Barracuda Networks firewall thinks that server has a bad reputation then that's good enough for them. They seem to think it's down to PN to either sort the server or get Barracuda to reset their firewall script.

Any road up, I shall forget it for now. Thanks for your help. Nobody from PN has responded so I guess it's a low priority.

[#10]

Doesn't look like avasout01 is on the Barracuda RBL at the time of writing. Are you still having problems?

[#11]

@bobpullen

Unfortunately yes. The recipient is being told that when receiving from avasout01 (sending via port 587 as mentioned) it triggers the "bad provider" error through their Barracuda script. Port 25 is ok and doesn't get rejected.

What do the first three blacklisted entries mean?

[#12]

The first three entries are other RBL's. I can't find a matching entry on SORBS to be concerned about but I've requested delisting from the other two. The fact remains though, that the Barracuda RBL does not see avasout as bad. Perhaps the recipient's script is feeding data in from some of the other providers? Either that, or they haven't updated it in a while.

There is absolutely no reason why the port should have any bearing on things, the public facing IP address for avasout01 is the same regardless of the port you're using. In addition to this, the port is only relevant between you and our relay server, not from our relay server to the recipient's mail server (which will be over port 25 regardless).

[#13]

I personally think it's more likely to be some sort of hardware problem at their end rather than a script being out of date. They aren't interested in trying to resolve it so it will have to remain a mystery. 

Thanks for responding anyway Bob.