[SOLVED] Outgoing SMTP connections blocked?

I'm trying to get sendmail working and posted my question here:


The answers question whether I can telnet to mailservers. Well, I cannot. For example

telnet 31045262.in2.mandrillapp.com 25

And nothing happens. I have nothing in /etc/hosts.deny
I feel like a noob, what should I try?

7 Replies

FWIW the Linode is in Dallas.

EDIT: It wasn't a Linode, my mistake!

I can telnet to that address from my linode server. Do you have some iptables rules setup for outgoing filtering/blocking? Maybe something is wrong with your config and it's flooded mandrillapp.com and they've blocked your IP? But I host my email server on my linode and I've never had an issue with ports being blocked.


No iptables or ufw.

Same problem if I try smtp.mail.yahoo.com or mail.protonmail.ch so I don't think they are blocking me.

It just hangs and does nothing, which is the same problem this guy has https://serverfault.com/questions/481448/cannot-telnet-to-port-25

Alright I feel dumb now, I have that VPS hosted at another company!

I was just looking at this when I noticed you edited your Stack Exchange post saying:

Solved: It was the ISP. I didn't think of this at first because I have multiple providers and the one I usually use doesn't block port 25. I opened a ticket and now just waiting to reboot. "We have removed the default SMTP block on your account."

I'm glad you were able to get this resolved!

We wanted to update this post with a link about our policy regarding mail server ports for new Linode customers. You can find more information about this in the below Community site post.

I just created my first Linode and I can't send emails. Why?

I only see 3 ports opened with nmap.
i'm not using any firewall (or I am?)

22/tcp open ssh
80/tcp open http
443/tcp open https

Who is blocking the other ports, and how I could open port 25?


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