Testing an Outbound Port from Your Web Host

Recently I decided to install the WP Mail SMTP plugin into a WordPress blog to get around the shared server being blacklisted. The idea is to get WordPress to send emails through an external mail server after authenticating. However on one server, the test mail was failing:  I was getting a timeout error.

After a little googling, I learned that some web hosts block certain outbound ports. But how to confirm whether my host was blocking port 587, used for SMTP over TLS?

Testing with portquiz.net

Enter portquiz.net. This brilliantly simple service is listening on all TCP ports and will respond to requests from http, telnet, nc, curl, and wget. Visit portquiz.net for examples.

I opened a Putty SSH session at each host and tested outbound port 587.

At one host, it fails:

netquiz 1

That explains why I couldn’t send email from that host using WP Mail SMTP.

Fortunately, at the host that is blacklisted, port 587 is open and WP Mail SMTP works:

netquiz 2

8 thoughts on “Testing an Outbound Port from Your Web Host

  1. Javier

    Dear friends i have wordpress with godaddy and i cant configured, do you know how port its a correct but godaddy hosting?
    thank you
    im from mexico

  2. sujit

    I have my port 587 test successful, even then unable to do the successful authentication.

  3. Mark Berry Post author

    sujit, email authentication is a big topic and there could be many reasons for a failure: unauthorized From address, bad password, etc. This post is only about resolving a timeout error that was caused by a blocked port.

  4. Jasa

    I have tried port 465, 25 and 587 blocked . My server Can not send email. What should i do tp lift up this error

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