ipfw is making contact with port 4021

Polytropon freebsd at edvax.de
Fri Jul 24 01:53:54 UTC 2020

On Thu, 23 Jul 2020 21:11:39 -0400, Ernie Luzar wrote:
> A firewall should not be making its own contact with any public ip 
> address. This is a security hole.

Allow me an addition:

As you now know that the IP belongs to a
company called "Envisacor", also note that port 4021
seems to have a designed purpose:

Port 4021 TCP and UDP are "nexus-portal", registered to
"Nexus Portal". Could that be a Cisco Nexus switch? Or
something by the Nexus company (IoT stuff)? Do you have
something like that in your network that might intend
to phone home?

However, this port could be used by something else, not
related to what I mentioned.



Again, I really doubt that ipfw is trying to make a
connection here; it's probably something else.

Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...

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