You can't deny just ping traffic with a standard access list, it is all or nothing.
Also, the extended ACL to allow the one-way telneting would be:
access-l 100 deny tcp host A host B eq telnet
access-l 100 permit ip any any
assuming you have a configuration something like hostA - rtr - hostB then access-l 100 should be put on the inbound interface closest to hostA.
This would stop the telnet traffic from A to B because the the source address is A, destination address B and destination port is telnet (23). It would have no effect on telnet from B to A because the access-l is inbound and there would not be a match on source & destination addresses anyway.
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...