Trying to open imap port but it appears filtered in the firewall

Question

I´m trying to configure a dovecot imap server but I´m having some problems with the imap port in my firewall.

I use the APF (advance policy firewall) for managing iptables on a centos server. I try to open the 143 port, but with every nmap, the port appears as "filtered", and I´m unable to connect to imap from the mail client.

Any idea? Thanks in advance!

Answer 1

I would test the port with telnet or ncat to make sure the firewall doesn't have something that blocks scans.

telnet imap-server-ip 143

If that doesn't work, post your iptables rules:

sudo iptables -L -v