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-   -   firewalld port should be open but it isn't (

mjbradakis 04-09-2019 06:16 PM

firewalld port should be open but it isn't
So I run this command:

[root@fizzer etc]# firewall-cmd --list-services
dhcpv6-client mdns samba-client smtp ssh

smtp is a listed service, the port is listed as open:

[root@fizzer etc]# firewall-cmd --list-ports
1025-65535/udp 1025-65535/tcp 25/tcp 80/tcp 22/tcp 143/tcp 25/udp

iptables-save also shows port 25 is available, postfix is running, but the server is not accepting connections on port 25:

[root@fizzer etc]# telnet 25
telnet: connect to address Connection refused

What is going on? Which programs are lying to me about port 25?


ferrari 04-09-2019 06:53 PM

What is reported by the following command?

ss -tulpn | grep :25

ferrari 04-09-2019 07:05 PM

FWIW, here's the results I got from a port scan of that public IP address...


~> nmap
Starting Nmap 7.70 ( ) at 2019-04-10 12:02 NZST
Nmap scan report for (
Host is up (0.19s latency).
Not shown: 846 closed ports, 152 filtered ports
22/tcp open  ssh
80/tcp open  http

Nmap done: 1 IP address (1 host up) scanned in 17.37 seconds

Check that your ISP is not blocking that port as well.

mjbradakis 04-09-2019 07:27 PM

I feel like such a chump. I was a sys admin in the computer science department at the U of U for about a quarter of a century, seen a lot of variations of UNIX based systems, etc. etc.

The problem here was amazingly easy to fix. I spelled the hostname correctly in and it works now.



ferrari 04-09-2019 08:10 PM

At least it was just a simple typo in the postfix configuration. Thanks for the update.

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