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What is on TCP Port 1999

We recently had a security scan which picked up that TCP Port 1999 was administratively prohibited. Further analysis indicated that an ACL on our ISP's router (Cisco 2500 on 11.3) is filtering any host communicating with the router on TCP Port 1999.

I am being asked to explain why this is and can find no reference on CCO other than:

This URL returned the document "NetRanger Version 2.2.1 Release Notes".

This however, does not shed any light. The IANA listing of port numbers show this to be "Cisco-Indentification-Port".

Can anyone enlighten me as to what is listening on Port 1999, what is exchanged over this port and what the vulnerabilities are, that would cause our ISP to block this with an ACL.

New Member

Re: What is on TCP Port 1999

port 1999 is a TCP-ID-Port for both TCP and UDP. It is a Cisco Indentification port. I'm not sure what it's used for, but I That's what that port is registered to according to RFC793(TCP) and RFC 768(UDP)

Eric Speake, MCSE, CCNA

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