CUCM hostname / ip address

BoredBored
in CCIE Collaboration Technical

from lab prospective if under system -> cisco unified cm we are given hostname instead of the ip address, is it advisable to change them to ip addresses.

is there a certein way of doing it or we can just replace the hostnames to ip address and it will not affect anything ??

 

 

Regards

Muhammad Kamran

 

Comments

  • brandonbrandon

    You must be "bored" and thinking to much into this :-p

     

    1 - Yes you can just simple change the hostname to IP and it should not break anything

     

    2 - Yes it is advisable to use IP address vs. hostname as you remove the reliance of DNS this way.

     

    On another note: I do not believe that this will actually change the hostname of the server itself though, if you SSH into the box and issue "show status" you will see the actual hostname configured for the server itself. If you have a name in CLI but IP under the list of CUCMs that is fine.

     

    Let me know if this answers your question.

  • michael.thompsonmichael.thompson
    Agreed.  I believe the reliance on DNS for phone usage is set during install.  It's worth noting that even when you tell it to use DNS, the server to server db sync still uses IP addy.  It does DNS resolution on boot and uses that IP address until rebooted. 



    Sent from my iPhone

    On May 6, 2013, at 7:57 AM, brandon <[email protected]> wrote:

    You must be "bored" and thinking to much into this :-p

     

    1 - Yes you can just simple change the hostname to IP and it should not break anything

     

    2 - Yes it is advisable to use IP address vs. hostname as you remove the reliance of DNS this way.

     

    On another note: I do not believe that this will actually change the hostname of the server itself though, if you SSH into the box and issue "show status" you will see the actual hostname configured for the server itself. If you have a name in CLI but IP under the list of CUCMs that is fine.

     

    Let me know if this answers your question.




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  • BoredBored

    i have to test this senerio out in the lab. 

    will let u know the results.

    how about the SYSTEM -> SERVER. the output here is always the hostnames of the servers.

    during installation there is no choice to enter ip address instead of the hostnames.

    and latter if you need change them, there are steps to follow.

     

    my question is if u are using the hostnames and there is no DNS configured how the phones are resolving the PUBLISHER and SUBSCRIBER address.

    maybe through the DHCP configuration ???

  • michael.thompsonmichael.thompson
    Bored,
       the System -> Server output always starts out as hostnames, similar to the Enterprise Parameters that show the hostname of the Publisher for all URLs.  The difference is that I think the latter is a more functional change required in order to use IP addresses over hostnames (the Enterprise Param change is absolutely necessary to avoid DNS from the phone).

        I think when referring to the phone CUCM Server Group configuration (primary and secondary CUCM Call Control), it is based off the initial installation process.  IF you tell it to use DNS based configuration, it populates the database with hostname (and will correspondingly require phones to use DNS).  If you tell it not to use DNS, it tells the phones to use IP addresses for it's host reference.


    I would have to get in and do a few test configurations to verify...but if anyone has some more insight at the database level...I'd be curious myself.

    On Monday, May 6, 2013, Bored wrote:

    i have to test this senerio out in the lab. 

    will let u know the results.

    how about the SYSTEM -> SERVER. the output here is always the hostnames of the servers.

    during installation there is no choice to enter ip address instead of the hostnames.

    and latter if you need change them, there are steps to follow.

     

    my question is if u are using the hostnames and there is no DNS configured how the phones are resolving the PUBLISHER and SUBSCRIBER address.

    maybe through the DHCP configuration ???




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    http://www.INE.com



    Subscription information may be found at:

    http://www.ieoc.com/forums/ForumSubscriptions.aspx
  • RahmRahm

    Configure the same as you see in "show myself" command. You only need to change the hostname to IP address in Enterprise parameters URLs for the phone.

     

  • ammarmalhotraammarmalhotra ✭

    Certificate issue or license re host issue

    1. Changing host name to IP address
    2. changing host name to fqdn
    3. adding DNS

    does these cause issue with public certificates or license.

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