Fiirewall- Set Up NAT Rules (OPNSense)

by Jan Bachelor
  • NAT rule for port 25
    • On OPNSense, go to Firewall → NAT → Port Forward and create a new rule.
    • Interface: your WAN
    • TCP/IP: IPv4
    • Protocol: TCP
    • Destination: WAN address
    • Destination port range: SMTP to SMTP (or select other and manually type in 25 to 25)
    • Redirect target IP: the IP of your mail server
    • Redirect target port: SMTP
    • Log it in for debugging purposes
    • Everything else leave as default or tweak as per your needs.
OPNSense Port Forward for Port 25 – SMTP in
  • NAT rule for port 993 (IMAPS)
    • On OPNSense, go to Firewall → NAT → Port Forward and create a new rule.
    • Interface: your WAN
    • TCP/IP: IPv4
    • Protocol: TCP
    • Destination: WAN address
    • Destination port range: IMAPS to IMAPS (or select other and manually type in 993 to 993)
    • Redirect target IP: the IP of your mail server
    • Redirect target port: IMAPS
    • Log it in for debugging purposes
    • Everything else leave as default or tweak as per your needs.
OPNSense Port Forward for Port 993 -IMAPS
  • NAT Rule for port 465 (SMPTS)
    • As above, use port 465 or SMTPS
OPNSense Port Forward for Port 465 – SMTPS out
  • Upon creation of the NAT rules, remember to click on the ‘Apply’ button in OPNSense to activate it.
Go back to course overview: Install iRedMail Mail Server As Proxmox VM With OPNSense As Firewall

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