Relation between host name,name and FQDN in CMDB

[Mahak2]

Hi all,

I am having a query related to the name ,Host name ,DNS Domain and FQDN fields of a CI.

How these fields are getting discovered and what is the relation between them.

I know there are some properties which determine these.

As far as i have observed in most cases name and Host name are same then why do we ave two fields which contain similar information?

Also FQDN in split into Host name and DNS Domain but in some we don't have FQDN but have the HOST name and DNS Domain.for ex-if FQDN is bosco.service-now.com Host name =bosco and DNS Domain=service-now.com

is it written in some script or senror to follow  some process which i am missing?

Lastly in some cases host name ,fqdn and Dns domain are in small letters while in some capital letters?

Inspite setting this property of "Host name case to upper case".

Can anyone help in understanding the login behind this?

Regards,

Mahak

[valarmathi_kann]

hi,

1. host_name , name --> both are same in CI

eg:- bosco.service-now.com

In the above example, it will be saved as

name = bosco & host_name = bosco & DNS domain = service-now.com

FQDN = bosco.service-now.com

2. There is a system property defined based on which the host_name can also be appended with domain name.

The system property is

glide.discovery.hostname.include_domain

Include domain name in host name: If "yes", include the domain name as part of the host name.  For example, "bosco.service-now.com" instead of "bosco".

3. There is also a system property which determines the case

glide.discovery.hostname.case

Host name case: If "Lower case" is selected, always translate the host name into lower case; if "Upper case" is selected, always translate the host name to upper case; if "No change" is selected, leave the host name intact. This primarily affects host names discovered with NETBIOS, though some non-standard DNS systems may also return some or all of the name in upper case.

4. We also have another system property which defines the fqdn based on regex.

 

Code is defined in HostnameJS script include.

[Mahak2]

Hello Valarmathi,

Thank you for providing the above information.

• I have one doubt is FQDN is split into Host Name and DNS Domain or the otherwise FQDN is made by combining the Host Name and DNS Domain.
• Also in our instance there are examples in which if fqdn is abc.service-now.com then host name is abc and DNS Domain is xyz.com ,what is the probable cause of this?
• And another concern is even after setting this Property glide.discovery.hostname.case to     UpperCase  we are having many hostnames in Lower case .
• Also in many examples FQDN is null but we have Host name and DNS Domain..how?

Can you please clear my above doubts?

Regards,

Mahak

[valarmathi_kann]

Hi,

1. I see we are parsing the FQDN 

you could see this format mathod code in HostnameJS script.

2. Also in our instance there are examples in which if fqdn is abc.service-now.com
then host name is abc and DNS Domain is xyz.com ,what is the probable cause of this?

This is the default behavior as I mentioned above. 

3. And another concern is even after setting this Property glide.discovery.hostname.case to     UpperCase  we are having many hostnames in Lower case . 

Check for any Reconciliation rules defined on the table or any other parent table in the hierarchy which restricts this.

4. I see this._parseFQDN(sysName); in HostNameJS script's format method. The parser would have failed based on the regular expression used.

[Ashutosh Munot1]

Hi,

All this is handled in Patterns and probes which you populates this information. This patterns and probes make use of properties which are defined in servicenow.

For ex: If we say we want to use DNS name then it will only populate your Domain Naming System name for that server.

Above property decides the FQDN name.

Now FQDN is the name defined in DNS and linked to database. COmbination of hostname and domain.

Hostname can be different that this.

Thanks,
Ashutosh