While setting up the IPtables rules for a new server, I set up Postfix and send an email to try it out. To my surprise the email arrived without me declaring a rule for the port in IPtables.
Additionally, I am using SquirrelMail and I had to make a rule specifically for it to being able to connect to using IMAP:
-A INPUT -p tcp -s 127.0.0.1 --dport 993 -j ACCEPT
When I previously inputed this rule to allow all connection on localhost
-A INPUT -i lo -j ACCEPT -A INPUT -d 127.0.0.0/8 -j REJECT
Probably I am making things wrongs, can you give me a clue?
This is what my IPtables rules looks like:
# Allow all loopback (lo0) traffic and drop all traffic to 127/8 that doesn't use lo0 -A INPUT -i lo -j ACCEPT -A INPUT -d 127.0.0.0/8 -j REJECT # Accept all established inbound connections -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT # Allow all outbound traffic - you can modify this to only allow certain traffic -A OUTPUT -j ACCEPT # Allow SSH connections -A INPUT -p tcp -m state --state NEW --dport 22 -j ACCEPT # Allow HTTP and HTTPS connections from anywhere -A INPUT -p tcp --dport 80 -j ACCEPT -A INPUT -p tcp --dport 443 -j ACCEPT # Allow IMAP connections only from localhost -A INPUT -p tcp -s 127.0.0.1 --dport 993 -j ACCEPT # Allow SVN server -A INPUT -p tcp --dport 3690 -j ACCEPT # Allow ping -A INPUT -p icmp -j ACCEPT # Log iptables denied calls -A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7 # Drop all other inbound - default deny unless explicitly allowed policy -A INPUT -j DROP -A FORWARD -j DROP COMMIT