ServiceNow custom url, lets encrypt, change to other CA

 set custom url:

https://docs.servicenow.com/bundle/washingtondc-platform-security/page/integrate/authentication/task/configure-custom-url.html

Add a custom URL to your instance configuration to use instead of your ServiceNow URL.

Before you begin

Role required: admin

You must activate the custom URL plugin and have purchased or registered a URL before adding the custom URL to your instance.

Procedure

1. Navigate to All > Custom URL > Custom URLs.
2. You should either:
   • Click New to associate a new domain name that is new to your instance.
   • Select a custom URL already set up to set as your instance URL.
3. Fill in the appropriate fields:
   Custom URL fields

   Field	Description
   Domain Name	Fully qualified domain name (FQDN) of the custom URL. The FQDN is a CNAME redirect created in the name server record for the custom domain. Note: For example, in the name server for acme.com, you might create an entry: support.acme.com 300 IN CNAME acme.servicenow.com
   Is Instance URL	Check box to enable this custom URL for all outbound URLs. Only one active custom URL can be the instance URL. To enable this setting for a custom URL, click Set as Instance URL on the URL record. Any previous custom URLs are then removed.
   Status	Status of the custom URL record. If the status is Active, the custom URL is provisioned and ready to use.
   Service Portal	Service portal that you want to use when you redirect users to your instance using the custom URL.
   Identity Provider	Identity Provider for the custom URL enables you to allow users to auto-redirect to specified IdPs defined at the custom URL record.

   A custom URL should activate within six hours on your instance. A background job polls for custom URL job completion every 30 minutes.

Also need to contact support.

*CNAME record for the sub domain

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finished domain will have cert from lets encrypt, to change, contact support or use 

plugin 

https://medium.com/@aashishatrey/a-custom-ssl-for-your-servicenow-custom-url-6e9b5bfd9898

1. Install the ServiceNow Infrastructure Security Settings (com.glide.infrastructure_security) plugin