Checking a linux server for smtp open gateway

How can I check that a specific Linux server is NOT acting as an open SMTP gateway?

Ideally I would like to put in a place a regular script to check one of our boxes on a regular basis.

Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.


Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
brothertomAuthor Commented:
Yes, I tried this earlier but I get

x.x.x.x on port 25... Error - could not connect to server

I figured the tool was broken - can someone try this against a known working server and see if you get the same error message?

That's what you should get if it's not allowed - in your config files you should have your allowed networks, if the IP does not match, it's not allowed to use the smtp server.

I personally use this tool:
According to you smtp daemon you should also check the documentation in order to find out how prevent your smtp to act as an open relay.

If using pop3 on the same host, you could try learning about pop-before-smtp (on google) if you do not have a large ammount of users.

It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.