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SMTP/FTP/TELNET Port Default Status?

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5 replies

by iootoo

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I have Network A connected to Router A, Network B connected to Router B, Router A and Router B are connected so that Network A & B can communicate. There is no defined any ACLs. My question is: What is the default port status of SMTP/FTP/TELNET in both router? Is it Open/Permit or Closed/Deny? Is defined ACLs will take effect even you don't apply it to any port of the router?

5 replies

by sgt_shultz

i am guessing it is open/permit. depends on the router. deny everything, open up what you need, probably only smtp and http

by joematus

With no ACLs, all access to the routers are open. The routers don't listen on smtp and ftp, but out of the box they'll listen to telnet. You need to create an ACL to limit the ip adresses that can telnet to the routers. Something along the lines of:

! Limit vty access by ip
access-list 10 permit 198.168.1.20
access-list 10 permit 198.168.1.21
access list 10 deny any

! Apply access by ACL
line vty 0 4
login authentication default
access-list 10 in

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