Bounced Emails

email_bounce

We’ve all been there… 

Its Friday morning and the your customer is expecting an important email, suddenly the sender calls and says: “We’re getting a bounce from your server, what’s going on, I’m waiting for this important email.”

They have a bounce message: “553 Message rejected – see http://dnsbl.invaluement.com/lookup/?item=10.3.11.37”

What does that mean? The IP address 10.3.11.37 has been black-listed on one of the lists we use and our server has rejected it as a result.

 

What can you do to fix?

There is no need to get in touch with us at this stage. Your customer needs to have look on their server to see whether there may be a problem that has caused it to be listed on one of the blocklists. If they are not running their own server then they need to contact their ISP.

Once the source of the problem is established you can request a de-list using the link in the rejection message. This should remove the mail server IP from that list once the database is refreshed.

Note: Attempting to remove the IP alone without solving the potential spam issue may risk you getting on a list for a longer period or permanently!

Hopefully the issue is now resolved and your customer’s email is moving freely again.

 

What Blacklists do we use?

There are quite a few out there and we have carefully selected the most efficient and accurate blacklists as part of our filtering engine.

However, some of them are over-zealous or poorly updated, which will potentially affect genuine emails. We avoid these!

We currently use Spamhaus and Invaluement (bounce messages from both are shown at the end of the article).

A particular note with regards to Spamhaus is that they have quite a high threshold: if your server, or your ISP’s server(s) are listed there then there is a serious spam problem
at your end!

 

Bounce Examples

Spamhaus:  553 Message rejected – see  http://www.spamhaus.org/query/bl?ip=10.3.11.37

Invaluement (used in the example): 553 Message rejected – see http://dnsbl.invaluement.com/lookup/?item=10.3.11.37