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Date:      Fri, 24 Jul 2020 03:53:50 +0200
From:      Polytropon <freebsd@edvax.de>
To:        Ernie Luzar <luzar722@gmail.com>
Cc:        "freebsd-questions@freebsd.org" <freebsd-questions@freebsd.org>
Subject:   Re: ipfw is making contact with 198.61.170.85 port 4021
Message-ID:  <20200724035350.ff89f558.freebsd@edvax.de>
In-Reply-To: <5F1A354B.7030508@gmail.com>
References:  <5F1A354B.7030508@gmail.com>

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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 198.61.170.85 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.

Source:

http://www.tcp-udp-ports.com/port-4021.htm

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



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



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