Cisco IOS Cheat Sheet – ROUTER COMMANDS

TERMINAL CONTROLS:

· Config# terminal editing – allows for enhanced editing commands

· Config# terminal monitor – shows output on telnet session

· Config# terminal ip netmask-format hexadecimal|bit-count|decimal – changes the format of subnet masks

HOST NAME:

· Config# hostname ROUTER_NAME

BANNER:

· Config# banner motd # TYPE MESSAGE HERE # – # can be substituted for any character, must start and finish the message

DESCRIPTIONS:

· Config# description THIS IS THE SOUTH ROUTER – can be entered at the Config-if level

CLOCK:

· Config# clock timezone Central -6
# clock set hh:mm:ss dd month yyyy – Example: clock set 14:35:00 25 August 2003

CHANGING THE REGISTER:

· Config# config-register 0x2100 – ROM Monitor Mode

· Config# config-register 0x2101 – ROM boot

· Config# config-register 0x2102 – Boot from NVRAM

BOOT SYSTEM:

· Config# boot system tftp FILENAME SERVER_IP – Example: boot system tftp 2600_ios.bin 192.168.14.2

· Config# boot system ROM

· Config# boot system flash – Then – Config# reload

CDP:

· Config# cdp run – Turns CDP on

· Config# cdp holdtime 180 – Sets the time that a device remains. Default is 180

· Config# cdp timer 30 – Sets the update timer.The default is 60

· Config# int Ethernet 0

· Config-if# cdp enable – Enables cdp on the interface

· Config-if# no cdp enable – Disables CDP on the interface

· Config# no cdp run – Turns CDP off

HOST TABLE:

· Config# ip host ROUTER_NAME INT_Address – Example: ip host lab-a 192.168.5.1
-or-

· Config# ip host RTR_NAME INT_ADD1 INT_ADD2 INT_ADD3 – Example: ip host lab-a 192.168.5.1 205.23.4.2 199.2.3.2 – (for e0, s0, s1)

DOMAIN NAME SERVICES:

· Config# ip domain-lookup – Tell router to lookup domain names

· Config# ip name-server 122.22.2.2 – Location of DNS server

· Config# ip domain-name cisco.com – Domain to append to end of names

CLEARING COUNTERS:

· # clear interface Ethernet 0 – Clears counters on the specified interface

· # clear counters – Clears all interface counters

· # clear cdp counters – Clears CDP counters

STATIC ROUTES:

· Config# ip route Net_Add SN_Mask Next_Hop_Add – Example: ip route 192.168.15.0 255.255.255.0 205.5.5.2

· Config# ip route 0.0.0.0 0.0.0.0 Next_Hop_Add – Default route
-or-

· Config# ip default-network Net_Add – Gateway LAN network

IP ROUTING:

· Config# ip routing – Enabled by default

· Config# router rip
-or-

· Config# router igrp 100

· Config# interface Ethernet 0

· Config-if# ip address 122.2.3.2 255.255.255.0

· Config-if# no shutdown

IPX ROUTING:

· Config# ipx routing

· Config# interface Ethernet 0

· Config# ipx maximum-paths 2 – Maximum equal metric paths used

· Config-if# ipx network 222 encapsulation sap – Also Novell-Ether, SNAP, ARPA on Ethernet. Encapsulation HDLC on serial

· Config-if# no shutdown

ACCESS LISTS:

IP Standard 1-99

IP Extended 100-199

IPX Standard 800-899

IPX Extended 900-999

IPX SAP Filters 1000-1099

IP STANDARD:

· Config# access-list 10 permit 133.2.2.0 0.0.0.255 – allow all src ip’s on network 133.2.2.0
-or-

· Config# access-list 10 permit host 133.2.2.2 – specifies a specific host
-or-

· Config# access-list 10 permit any – allows any address

· Config# int Ethernet 0

· Config-if# ip access-group 10 in – also available: out

IP EXTENDED:

· Config# access-list 101 permit tcp 133.12.0.0 0.0.255.255 122.3.2.0 0.0.0.255 eq telnet
-protocols: tcp, udp, icmp, ip (no sockets then), among others
-source then destination address
-eq, gt, lt for comparison
-sockets can be numeric or name (23 or telnet, 21 or ftp, etc)
-or-

· Config# access-list 101 deny tcp any host 133.2.23.3 eq www
-or-

· Config# access-list 101 permit ip any any

· Config# interface Ethernet 0

· Config-if# ip access-group 101 out

IPX STANDARD:

· Config# access-list 801 permit 233 AA3 – source network/host then destination network/host
-or-

· Config# access-list 801 permit -1 -1 – “-1” is the same as “any” with network/host addresses

· Config# interface Ethernet 0

· Config-if# ipx access-group 801 out

IPX EXTENDED:

· Config# access-list 901 permit sap 4AA all 4BB all
– Permit protocol src_add socket dest_add socket
-“all” includes all sockets, or can use socket numbers
-or-

· Config# access-list 901 permit any any all any all
-Permits any protocol with any address on any socket to go anywhere

· Config# interface Ethernet 0

· Config-if# ipx access-group 901 in

IPX SAP FILTER:

· Config# access-list 1000 permit 4aa 3 – “3” is the service type
-or-

· Config# access-list 1000 permit 4aa 0 – service type of “0” matches all services

· Config# interface Ethernet 0

· Config-if# ipx input-sap-filter 1000 – filter applied to incoming packets
-or-

· Config-if# ipx output-sap-filter 1000 – filter applied to outgoing packets

NAMED ACCESS LISTS:

· Config# ip access-list standard LISTNAME
-can be ip or ipx, standard or extended
-followed by the permit or deny list

· Config# permit any

· Config-if# ip access-group LISTNAME in
-use the list name instead of a list number
-allows for a larger amount of access-lists

PPP SETUP:

· Config-if# encapsulation ppp

· Config-if# ppp authentication chap pap
-order in which they will be used
-only attempted with the authentification listed
-if one fails, then connection is terminated

· Config-if# exit

· Config# username Lab-b password 123456
-username is the router that will be connecting to this one
-only specified routers can connect
-or-

· Config-if# ppp chap hostname ROUTER

· Config-if# ppp chap password 123456
-if this is set on all routers, then any of them can connect to any other
-set same on all for easy configuration

ISDN SETUP:

· Config# isdn switch-type basic-5ess – determined by telecom

· Config# interface serial 0

· Config-if# isdn spid1 2705554564 – isdn “phonenumber” of line 1

· Config-if# isdn spid2 2705554565 – isdn “phonenumber” of line 2

· Config-if# encapsulation PPP – or HDLC, LAPD

DDR – 4 Steps to setting up ISDN with DDR

1. Configure switch type
Config# isdn switch-type basic-5ess – can be done at interface config
2. Configure static routes
Config# ip route 123.4.35.0 255.255.255.0 192.3.5.5 – sends traffic destined for 123.4.35.0 to 192.3.5.5
Config# ip route 192.3.5.5 255.255.255.255 bri0 – specifies how to get to network 192.3.5.5 (through bri0)
3. Configure Interface
Config-if# ip address 192.3.5.5 255.255.255.0
Config-if# no shutdown
Config-if# encapsulation ppp
Config-if# dialer-group 1 – applies dialer-list to this interface
Config-if# dialer map ip 192.3.5.6 name Lab-b 5551212
connect to lab-b at 5551212 with ip 192.3.5.6 if there is interesting traffic
can also use “dialer string 5551212” instead if there is only one router to connect to
4. Specify interesting traffic
Config# dialer-list 1 ip permit any
-or-
Config# dialer-list 1 ip list 101 – use the access-list 101 as the dialer list
5. Other Options
Config-if# hold-queue 75 – queue 75 packets before dialing
Config-if# dialer load-threshold 125 either
-load needed before second line is brought up
-“125” is any number 1-255, where % load is x/255 (ie 125/255 is about 50%)
-can check by in, out, or either
Config-if# dialer idle-timeout 180
-determines how long to stay idle before terminating the session
-default is 120

FRAME RELAY SETUP:

· Config# interface serial 0

· Config-if# encapsulation frame-relay – cisco by default, can change to ietf

· Config-if# frame-relay lmi-type cisco – cisco by default, also ansi, q933a

· Config-if# bandwidth 56

· Config-if# interface serial 0.100 point-to-point – subinterface

· Config-if# ip address 122.1.1.1 255.255.255.0

· Config-if# frame-relay interface-dlci 100
-maps the dlci to the interface
-can add BROADCAST and/or IETF at the end

· Config-if# interface serial 1.100 multipoint

· Config-if# no inverse-arp – turns IARP off; good to do

· Config-if# frame-relay map ip 122.1.1.2 48 ietf broadcast
-maps an IP to a dlci (48 in this case)
-required if IARP is turned off
-ietf and broadcast are optional

· Config-if# frame-relay map ip 122.1.1.3 54 broadcast

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