Turning Off unwanted Services in Cisco Routers

General Services
Now we will disable Cisco Discover Protocol at layer 2.

router1#config t

router1(config)# no cdp run

Now we will disable tcp and udp small servers

router1(config)# no service tcp-small-servers

router1(config)# no service udp-small-servers

Now we will disable Finger service

router1(config)# no ip finger

router1(config)# no service finger

Now we will disable HTTP Server

router1(config)# no ip http server

Now we will disable bootp server to prevent other system booting over network

router1(config)# noip bootp server

Now we will disable SNMP

router1(config)# no snmp-server community public RO

router1(config)# no snmp-server community private TW

router1(config)# no snmp-server enable traps

router1(config)# no snmp-server system-shutdown

router1(config)# no snmp-server trap-auth

router1(config)# no snmp-server

Now we will disable DNS lookup to broadcast addresses

router1(config)# no ip domain-lookup

Now we will disable Auto Loading

router1(config)# no boot network

router1(config)# no service config

Now we will disable IP source Routing

router1(config)# no  ip source-route

Now we will see about disabling Interface services

Now we will disable IP Directed Broadcast

router1(config)# interface eth1

router1(config-if)# no ip directed-broadcast

Now we will disable ICMP

router1(config)# interface eth1

router1(config-if)# no ip redirect

router1(config-if)# no ip unreachable

router1(config-if)# no ip mask-reply

router1(config-if)# end

Now we will disable Address Resolution Protocol over different LAN.

router1(config)# no  ip proxy-arp

Now we will disable NTP

router1(config)#access-list 101 deny [ntp|tcp] any any eq 123

router1(config)#interface eth1

router(config-if)#ip access-group 101 in

router(config-if)#ntp disble

router(config-if)#end

         
Now we will disable unused Interfaces

router1#config t

router1(config)#interface eth2

router1(config-if)#shutdown

router1(config-ig)#end