Forum Discussion

MeAndMyBIGIP_60's avatar
MeAndMyBIGIP_60
Icon for Nimbostratus rankNimbostratus
Feb 19, 2010

FQDN Heads-up

In the Release Notes (https://support.f5.com/kb/en-us/products/big-ip_ve/releasenotes/product/relnotes_ve_10_1_0.htmlconfig_setup)

 

 

"In the Host Name box, retain or change the host name of the local system.

 

You must enter a fully qualified domain name (FQDN) for the system. You must type letters, numbers, and/or the characters underscore ( _ ), dash ( - ) and period ( . )."

 

 

You can't use underscores, or you'll continue to get "You must use a fully-qualified DNS Name"
ve
virtualization
  • treepose_102627's avatar
    treepose_102627
    Historic F5 Account
    Feb 19, 2010
    You can use an underscore in the hostname. You must specify at least a dot for the hostname to have it recognized as an FQDN.

     

     

    "b system hostname bigip_ltm_ve" is not valid

     

     

    "b system hostname bigip_ltm_ve.trial" is.

     

     

  • MeAndMyBIGIP_60's avatar
    MeAndMyBIGIP_60
    Icon for Nimbostratus rankNimbostratus
    Feb 19, 2010
    @treepose

     

     

    I had tried various combinations of "my_new_hostname.domain.com" "my_new_hostname.subname.domain.com" etc, and kept getting the error. Couldn't get it to go away until I changed it to "MyNewHostname.sub.domain.com"

     

     

    Me.
  • John_Hall_11177's avatar
    John_Hall_11177
    Historic F5 Account
    Feb 19, 2010
    Unfortunately, F5 is stuck between a rock ( RFC 952: http://tools.ietf.org/html/rfc952 ) and a hard place ( Microsoft http://technet.microsoft.com/en-us/library/cc779857%28WS.10%29.aspx ). There's more discussion on the Hostname wikipedia page: http://en.wikipedia.org/wiki/Hostname, under "Restrictions on valid host names". Admittedly, it looks like the help text and the validation code do not agree in this instance.
  • hwidjaja_37598's avatar
    hwidjaja_37598
    Icon for Altostratus rankAltostratus
    Feb 21, 2010
    @MeAndMyBIGIP

    I could set the hostname using CLI to my_new_hostname.domain.com and my_new_hostname.subname.domain.com but not from GUI: 

        
 [root@my_new:Active] config  b system hostname my_new_hostname.domain.com    
       
 [root@my_new_hostname:Active] config  b system hostname    
 SYSTEM - Local Host Name: my_new_hostname.domain.com    
        
 [root@my_new_hostname:Active] config  b system hostname my_new_hostname.subname.domain.com    
       
 [root@my_new_hostname:Active] config  b system hostname    
 SYSTEM - Local Host Name: my_new_hostname.subname.domain.com

    I'm not sure whether or not GUI's error is a bug. I personally will not use underscore in the hostname as it's not compliant with the RFC.
  • Hamish's avatar
    Hamish
    Icon for Cirrocumulus rankCirrocumulus
    Mar 29, 2010
    Yeah. Underscores should be avoided at all costs. In theory they're invalid in the RFC's, and a some DNS servers won't allow them. Where they are supported, they tend to be used as special characters for finding services. e.g. _ldap.your.domain.

     

     

    I don't believe the two references quoted above are necessarily at odds with each other. Much as appreciate a good like MS bashing where they go off and ignore established standards, whoever wrote the article there is being pretty good. Saying to avoid underscores for hostnames, but that they do tend (i.e. Have been proposed) to get used for services to avoid clashing with host namespaces.

     

     

    H