if you please I wanna ask how to apply standard Acl on the server,to deny any communication between it and the hosts connected to Houston router.

There is no CLI in the server or hosts to write a command

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  • You can apply an ACL on the router, but server configuration is off-topic on this forum. You can try asking on Server Fault.
    – Ron Trunk
    Commented Nov 11, 2018 at 17:44
  • 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 provide and accept your own answer.
    – Ron Maupin
    Commented Dec 25, 2018 at 9:56

1 Answer 1


You can use standard ACL(Access control list). Standard access list will match traffic based on source ip address or source network subnet.

Extended ACLs can match both source and destination subnet or ip address and also traffic type.

So then you can either deny or allow the traffic. For example if you want to deny traffic from server then

R1(config)#access-list 1 deny 
R1(config)#access-list 1 permit an
R1(config)#access-list 1 permit any 
R1(config)#int fa0/0
R1(config-if)#ip access-group 1 ?
  in   inbound packets
  out  outbound packets

R1(config-if)#ip access-group 1 in 

Remember you need an explicit permit statement at the end since you don't want traffic from other hosts to be denied as well since there is an explicit deny statement by default at the end of ACL's.

Hope it made sense to you.

You can read more about access control lists here. https://www.cisco.com/c/en/us/support/docs/security/ios-firewall/23602-confaccesslists.html

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