How to block telnet access for one particular network from all networks except one using Extended ACL

Question

Scenerio is given in the picture. I want to block all the networks except 192.168.5.128/25 from doing telnet of 192.168.5.0/25.

Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can post and accept your own answer. — Ron Maupin, Nov 19, 2022 at 22:45

Zac67 · Accepted Answer · 2020-12-16 12:15:48Z

0

On Switch0, you permit the single source subnet for telnet you want, deny all other telnet connections and then permit everything else.

1000 permit tcp 192.168.5.128/25 192.168.5.0/25 eq 23
1010 deny tcp any 192.168.5.0/25 eq 23
9999 permit ip any any

answered Dec 16, 2020 at 12:15

Zac67♦

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Unless the switch is layer 3, that ACL has to go on Router 0.
– Ron Trunk
Dec 16, 2020 at 15:27
The 2960 should support extended ACLs. Putting it on the router doesn't prevent telnet from within 192.168.5.0/25.
– Zac67 ♦
Dec 16, 2020 at 18:39

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