ipfw is making contact with port 4021

Jon Radel jon at radel.com
Fri Jul 24 01:37:17 UTC 2020

On 7/23/20 21:11, Ernie Luzar wrote:
> A firewall should not be making its own contact with any public ip
> address. This is a security hole.
> I have not played with ipfw since before it was rewritten to become
> ipfw2 so I do not know when this internal "call home"  function was
> added. pf and ipf are not doing this. I block it to be secure.
> Can any one provide any info about this?
What type of network is behind this firewall?

There any chance there's a security system with an EnvisaLink module
involved somewhere on that network?


--Jon Radel
jon at radel.com

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 4177 bytes
Desc: S/MIME Cryptographic Signature
URL: <http://lists.freebsd.org/pipermail/freebsd-questions/attachments/20200723/06d5fb6c/attachment.bin>

More information about the freebsd-questions mailing list