Help using cisco DDNS for updating dynamic IP

Comments

9 comments

  • Avatar
    stoobie

    Router DDNS config

    ip ddns update method dnsomatic
    HTTP
    add http://[email@address]:[password]@updates.dnsomatic.com/nic/update?hostname=all.dnsomatic.com&myip=<a>
    remove http://[email@address]:[password]@updates.dnsomatic.com/nic/update?hostname=all.dnsomatic.com&myip=<a>
    interval maximum 1 0 0 0
    interval minimum 0 6 0 0

    interface FastEthernet4
    ip dhcp client update dns server both
    ip ddns update hostname all.dnsomatic.com
    ip ddns update dnsomatic
    ip address dhcp
    ip verify unicast source reachable-via rx allow-default 100
    no ip redirects
    no ip unreachables
    no ip proxy-arp
    ip nat outside
    ip virtual-reassembly
    speed auto
    full-duplex

     

  • Avatar
    rotblitz

    Enter the exact same update URL in a browser and see what is really returned.

  • Avatar
    stoobie

    I  forgot to add that to original post, when I put that URL in a browser it returns "good xx.xx.xx.xx" and the update shows in my dnsomatic history as a successful update.

  • Avatar
    rotblitz

    Then the problem is with your Cisco 871, and you'll want to refer to Cisco support.  Most likely nobody can help you here, because the issue is not related to DNS-O-Matic, but to this update client.

  • Avatar
    matthew.john

    Stoobie, did you ever get this sorted. I have the exact same issue? 

  • Avatar
    adventurer007

    Now in 2019 I have exactly the same issue.

    After much troubleshooting and comparing config with No-ip, I came to the conclusion that Dnsomatic is never going to work on a Cisco router because of the add string format.

    For Dnsomatic email in this string has to be example someone@somewhere.com

    add http://[email@address]:[password]@updates.dnsomatic.com/nic/update?hostname=all.dnsomatic.com&myip=<a>

     

    Comparing with a proven working No-ip config which use,

    add http://username:password@dynupdate.no-ip.com/nic/update?hostname=<h>&myip=<a>

     

    I think Cisco router is sensitive to the @ symbol appearing twice in the string, so it's never going to work with Dnsomatic.

  • Avatar
    rotblitz

    Try with replacing the @ character in the email address by %40

  • Avatar
    adventurer007

    Very clever trick, i'm not a programmer i wouldn't think of using hex.

    Anyway it works ! I'm posting the final config here for the benefit of the community.

    This has been tested on IOS-XE 16.8.2

     

    ip ddns update method dnsomatic
    HTTP
    add http://someone%40somewhere.com:password@updates.dnsomatic.com/nic/update?hostname=all.dnsomatic.com&myip=<a>
    interval maximum 0 8 0 0
    interval minimum 0 0 5 0

    ip ddns update hostname your.no-ip.hostname
    ip ddns update dnsomatic

     

    In debug you will see these, the important part is "good x.x.x.x" this will indicate successful. If this line is missing then something is still wrong.

    HTTPDNSUPD: Sending request

    HTTPDNSUPD: Response for update your.no-ip.hostname <=> x.x.x.x

    HTTPDNSUPD: DATA START
    good x.x.x.x
    HTTPDNSUPD: DATA END, Status is Response data recieved, successfully

  • Avatar
    rotblitz

    Brilliant!

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