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Forums » CCIE Forums » CCIE Service Provider General » today i got some thing i have never seen on trace route [!H]
Latest post 01-17-2010 11:34 AM by Ahenning. 5 replies.
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  • 01-16-2010 3:03 AM

    today i got some thing i have never seen on trace route [!H]

    Reply Contact

    what does ! H symbol on traceroute means?

     

    is it host not reachable 

     

    Hope for best prepare for worst

    Paks Kal 
    • Post Points: 50

  • 01-16-2010 4:50 AM In reply to

    • Seba
    • Top 25 Contributor
    • Joined on 07-17-2008
    • Ireland
    • Expert
    • Points 3,680

    Re: today i got some thing i have never seen on trace route [!H]

    Reply Contact

    Hi,

    Link - http://www.cisco.com/en/US/tech/tk364/technologies_tech_note09186a00801ae32a.shtml#addno

    "In Cisco routers, the codes for a traceroute command reply are: 

    ! -- success
    * -- time out
    N -- network unreachable
    H -- host unreachable
    P -- protocol unreachable
    A -- admin denied
    Q -- source quench received (congestion)
    ? -- unknown (any other ICMP message)"

    Side note - if you are thinking about CCIE you need to be more proactive in searching things like this. In this case I used google search "cisco traceroute h" and it was first link on the list.

    Good luck with your study.
    Cheers,

    Seba

    Sebastian Pasternacki

    CCIE #17541 RS/Sec/SP
    • Post Points: 5

  • 01-16-2010 10:42 AM In reply to

    Re: today i got some thing i have never seen on trace route [!H]

    Reply Contact
    Yes indeed

    On Jan 16, 2010, at 6:11 AM, scrlk wrote:

    what does ! H symbol on traceroute means?

     

    is it host not reachable 

     



    Internetwork Expert - The Industry Leader in CCIE Preparation
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    • Post Points: 5

  • 01-16-2010 5:03 PM In reply to

    Re: today i got some thing i have never seen on trace route [!H]

    Reply Contact

    Usually an ACL blocking the traffic somewhere does that.
    • Post Points: 20

  • 01-17-2010 9:03 AM In reply to

    Re: today i got some thing i have never seen on trace route [!H]

    Reply Contact

    Thanks for the help 

    i'll take care about it 

    Hope for best prepare for worst

    Paks Kal 
    • Post Points: 20

  • 01-17-2010 11:34 AM In reply to

    Re: today i got some thing i have never seen on trace route [!H]

    Reply Contact

    Quite a common thing in networks that for some reason has a lot of static routes and is easy to replicate:

     

    R1(config)#ip route 200.200.200.200 255.255.255.255 12.12.12.2

    R1#traceroute 200.200.200.200

     

      1 12.12.12.2 4 msec 4 msec 8 msec

      2 12.12.12.2 !H  *  !H 

     

    Now the trick is to make the unreachable message go away. On R2: no ip unreachables

    http://21500.net
    • Post Points: 5
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