Cisco commands you didnt know that you needed to know.

HondabuffHondabuff Member Posts: 667 ■■■□□□□□□□
in CCNP
I wanted to start a thread to see what cool commands are out there that you use that is not a well known command.

I will start with my 3 favorites!

Router#who

Router#show cry ses
"Shows vpn session"

Router#test interfaces
“The problem with quotes on the Internet is that you can’t always be sure of their authenticity.” ~Abraham Lincoln
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  • theodoxatheodoxa Member Posts: 1,340 ■■■■□□□□□□
    # show ip ospf rib

    It lists any tags that have been applied to an OSPF route and if that route has been installed in the routing table or not.
    R&S: CCENT → CCNA → CCNP → CCIE [ ]
    Security: CCNA [ ]
    Virtualization: VCA-DCV [ ]
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  • linuxabuserlinuxabuser Member Posts: 97 ■■□□□□□□□□
    clear interface

    to bounce (stop/restart) an interface.
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  • HondabuffHondabuff Member Posts: 667 ■■■□□□□□□□
    Router#clear ip dhcp binding *

    Clears all DHCP addresses.
    “The problem with quotes on the Internet is that you can’t always be sure of their authenticity.” ~Abraham Lincoln
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  • d4nz1gd4nz1g Member Posts: 464
    archive - found this while looking for an automated config backup solution lol
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  • RouteMyPacketRouteMyPacket Member Posts: 1,104
    I know every single config command ever:

    ?

    icon_lol.gif
    Modularity and Design Simplicity:

    Think of the 2:00 a.m. test—if you were awakened in the
    middle of the night because of a network problem and had to figure out the
    traffic flows in your network while you were half asleep, could you do it?
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  • networker050184networker050184 Mod Posts: 11,962 Mod
    But what about the hidden commands?!
    An expert is a man who has made all the mistakes which can be made.
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  • HondabuffHondabuff Member Posts: 667 ■■■□□□□□□□
    Router#wr
    Building configuration...
    [OK]

    and

    R1#test crash
    WARNING: Command selections marked with '(crash router)' will crash
    router when issued. However a selection 'C' will need to
    be issued IMMEDIATELY before these selections to enable them.

    Type the number for the selected crash:
    1 (crash router) Bus Error, due to invalid address access
    2 (crash router) Bus Error, due to parity error in Main memory
    3 (crash router) Bus Error, due to parity error in I/O memory
    4 (crash router) Address Error, due to fetching code from odd address
    5 (crash router) Jump to zero
    6 (crash router) Software forced crash
    7 (crash router) Illegal read of address zero
    8 (crash router) Divide by zero
    9 (crash router) Corrupt memory
    C Enable crash router selection marked with (crash router)
    R (crash router) User enter read bus error address
    U (crash router) User enter write bus error address
    W (crash router) Software watchdog timeout (*** Watch Dog Timeout ***)
    w (crash router) Process watchdog timeout (SYS-2-WATCHDOG)
    d Disable crashinfo collection
    e Enable crashinfo collection
    i Display contents of current crashinfo flash file
    m Write crashinfo on crashinfo RAM
    n Change crashinfo flash file name
    q Exit crash menu
    s Save crashinfo to current crashinfo flash file
    c Close current crashinfo flash file
    t Write crashinfo on console TTY
    x Exit crash menu
    “The problem with quotes on the Internet is that you can’t always be sure of their authenticity.” ~Abraham Lincoln
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  • Legacy UserLegacy User Unregistered / Not Logged In Posts: 0 ■□□□□□□□□□
    #more system:running-config

    -Used for finding the Site to Site preshared key
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  • xnxxnx Member Posts: 464 ■■■□□□□□□□
    theodoxa wrote: »
    # show ip ospf rib

    It lists any tags that have been applied to an OSPF route and if that route has been installed in the routing table or not.
    I learnt this one recently too
    Getting There ...

    Lab Equipment: Using Cisco CSRs and 4 Switches currently
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  • gorebrushgorebrush Member Posts: 2,743 ■■■■■■■□□□
    test crash? Hohoo going to try that one
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  • RouteMyPacketRouteMyPacket Member Posts: 1,104
    dmarcisco wrote: »
    #more system:running-config

    -Used for finding the Site to Site preshared key

    On the ASA platform only
    Modularity and Design Simplicity:

    Think of the 2:00 a.m. test—if you were awakened in the
    middle of the night because of a network problem and had to figure out the
    traffic flows in your network while you were half asleep, could you do it?
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  • aaron0011aaron0011 Member Posts: 330
    debug capwap console cli is required first before you can run the archive command on a CAPWAP to upgrade the IOS. The version on this particular AP wouldn't register to the vWLC. Pretty obscure but good one to know if you work with wireless at all.
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  • JeanMJeanM Member Posts: 1,117
    #csim start is my fave while learning voice stuff discovered it .

    Cisco CSIM (Call Simulation) – Hidden IOS Command « Mark Holloway
    2015 goals - ccna voice / vmware vcp.
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  • Legacy UserLegacy User Unregistered / Not Logged In Posts: 0 ■□□□□□□□□□
    JeanM wrote: »
    #csim start is my fave while learning voice stuff discovered it .

    Cisco CSIM (Call Simulation) – Hidden IOS Command « Mark Holloway

    I wonder if that that cmd is really used in a live setting? When I came across it some time ago I read somewhere its undocumented because when people used that cmd it crashed there routers.
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  • aquillaaquilla Member Posts: 148 ■■■□□□□□□□
    dmarcisco wrote: »
    I wonder if that that cmd is really used in a live setting? When I came across it some time ago I read somewhere its undocumented because when people used that cmd it crashed there routers.

    I used this command a while back. Simulated the call successfully then the router stopped responding :o

    As you say, that command crashed the router and forced it reload. Not really what I wanted in the middle of a nightshift with the router a couple of hundred miles away.
    Regards,

    CCNA R&S; CCNP R&S
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  • aquillaaquilla Member Posts: 148 ■■■□□□□□□□
    BGP backdoor - Came across this the other day.

    Cisco IOS IP Routing: BGP Command Reference - BGP Commands: neighbor timers through show bgp nsap summary [Support] - Cisco
    Regards,

    CCNA R&S; CCNP R&S
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  • Legacy UserLegacy User Unregistered / Not Logged In Posts: 0 ■□□□□□□□□□
    aquilla wrote: »
    I used this command a while back. Simulated the call successfully then the router stopped responding :o

    As you say, that command crashed the router and forced it reload. Not really what I wanted in the middle of a nightshift with the router a couple of hundred miles away.

    Well now i'm definitely not ever going to use that cmd lol.
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  • JeanMJeanM Member Posts: 1,117
    Well, it works in a lab and haven't crashed once yet icon_lol.gif
    2015 goals - ccna voice / vmware vcp.
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  • theodoxatheodoxa Member Posts: 1,340 ■■■■□□□□□□
    I got a little dyslexic and discovered a new command

    # show ip ospf route
    R&S: CCENT → CCNA → CCNP → CCIE [ ]
    Security: CCNA [ ]
    Virtualization: VCA-DCV [ ]
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  • stlsmoorestlsmoore Member Posts: 515 ■■■□□□□□□□
    show ip route longer-prefixes
    My Cisco Blog Adventure: http://shawnmoorecisco.blogspot.com/

    Don't Forget to Add me on LinkedIn!
    https://www.linkedin.com/in/shawnrmoore
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  • HondabuffHondabuff Member Posts: 667 ■■■□□□□□□□
    Another cool command some of you might know is the auto state command. I had to add another VLAN to router at our Stanford site and our field tech wasn't plugging anything in until Monday. Normally the SVI will not ping through the VPN but toss on the no auto state command on the VLAN and viola! Ping away with nothing plugged into it.
    “The problem with quotes on the Internet is that you can’t always be sure of their authenticity.” ~Abraham Lincoln
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