Changing the DNS or URL (host header) in SharePoint 2007 Site

Basic Details:

For changing the host header (and more), check out Alternate Access Mappings.  You will find this under the Operations tab and Global Configuration section.  Click "Edit Public URLs" and be sure to have the correct web application selected before you make any changes.

Scenario:If you have developed the sharepoint site with url http://xyz:47089 and xyz is machine name and later you have mapped with any public IP then you will be able  to access only home page but you can not access other resources and page that is bindup with all links available in site. In this case, you can change URL by Alternate access mappings.

Solution:

Step[1]: Open Sharepoint Central Admin & go to Operations tab



Step[2]: Under Global configuration heading select Alternate access mappings.



Step[3]: Select the desired web application i.e. http://xyz:47089 (in this example)






Step[4]: On Edit Internal URLs page set the change the value of http://xyz1:47089 to http://155.23.84.70:47089.



Step[5]: Now this site[http://155.23.84.70:47089] will be accessible throughout the intranet from any domain.

Note: The same you can map with Public IP for e.g. 155.23.84.70 and you just need to  provide windows authetication to this site.