Configure Namecheap DNS For Google App Engine Custom Domains

After configuring Google App Engine - Mapping Custom Domain, proceed to setup your Namecheap DNS.

Login into Namecheap, goto Domain List -> Find your domain and click Manage -> Advance DNS.

Click ADD NEW RECORD, select A Record, set @ for Host, and 216.239.32.21 for IP Address. Repeat this step until the following are setup.

A Record    @   216.239.32.21   Automatic
A Record    @   216.239.34.21   Automatic
A Record    @   216.239.36.21   Automatic
A Record    @   216.239.38.21   Automatic

Click ADD NEW RECORD, select AAAA Record, set @ for Host, and 2001:4860:4802:32::15 for IPv6. Repeat this step until the following are setup.

AAAA Record @   2001:4860:4802:32::15   Automatic
AAAA Record @   2001:4860:4802:34::15   Automatic
AAAA Record @   2001:4860:4802:36::15   Automatic
AAAA Record @   2001:4860:4802:38::15   Automatic

There should be an existing CNAME entry for www. Edit it to change its Target/Value to ghs.googlehosted.com.. Change TTL to Automatic.

CNAME       @   ghs.googlehosted.com.   Automatic