Cisco Telnet Access is the most common access to a router or switch, but, however is not secure but there are some tricks to apply and enchance the security. For those tasks I use Putty Client. So we ´re going to mixed two concepts viewed in older posts, ACL and vty Access. You can enhance your security applying a ACL on the vty config, let`s go! – Config ACL
R1(config)#ip access-list extended vtyAccess R1(config)#permit tcp host 10.0.53.0 0.0.0.255 any eq telnet log R1(config)#permit tcp any any eq 22 log R1(config)#deny tcp any any log
– Apply on vty config
R1(config)#line vty 0 4 R1(config-line)#access-class vtyAccess in
if you need more information go to cisco.comor contact me using the form. Hope it helps you!