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:
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)
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
Introduction Featured Speakers Luis Espejel is the Telecommunications
Manager of IENova, an Oil & Gas company. Currently he works with Cisco
IOS® and Cisco IOS XE platforms, and NX to some extent. He has also
worked as a Senior Engineer with the Routing P...
In this session you can learn more about Layer 3 multicast and the best
practices to identify possible threats and take security measures. It
provides an overview of basic multicast, the best security practices for
use of this technology, and recommendati...