pFSense 2.6.0 Port 0

Networking & Firewalls
1

I ran an external scan on pFSense 2.6.0 and it came back with, “TCP port 0 is open on the remote host. This is highly suspicious as this TCP port is reserved and should not be used. This might be a backdoor (REx).”

  1. Should Port 0 be blocked/closed?
  2. If it should be blocked/closed, how do you go about it?
2

Additional information
In /etc/inc/filter.inc there are two port 0 lines:

We use the mighty pf, we cannot be fooled.

block {$log[‘block’]} quick inet proto { tcp, udp } from any port = 0 to any ridentifier {$increment_tracker()} label “Block traffic from port 0”
block {$log[‘block’]} quick inet proto { tcp, udp } from any to any port = 0 ridentifier {$increment_tracker()} label “Block traffic to port 0”

In an older post these lines were formatted differently (version 2.4.xx?):

block {$log['block']} quick inet proto { tcp, udp } from any port = 0 to any tracker {$increment_tracker($tracker)} label "Block traffic from port 0"
block {$log['block']} quick inet proto { tcp, udp } from any to any port = 0 tracker {$increment_tracker($tracker)} label "Block traffic to port 0"
3

Port 0 is not really used and is blocked.
https://www.reddit.com/r/PFSENSE/comments/fnb0fg/port_0_closed/

4

That is what I would expect based on the “We use the mighty pf, we cannot be fooled” script but OpenVAS still detects it. Wondering if it is an issue with OpenVAS.