Here are my lessons learned regarding the azure application gateway:
1.) Application gateway does _not_ support statically addressed public IPs
2.) Application gateway does _not_ support public IPs with a DNS name (e.g. somename.cloudapp.net)
3.) The application gateway’s DNS name _should_ be used to create a CNAME record which points to a friendly DNS (i.e. myawesomesite.com)
4.) The use of an A-record is _not_ recommended because the VIP may change on restart of the application gateway
Run this powershell script to get the gateway DNS:
Login-AzureRmAccount
Set-AzureRmContext -SubscriptionName '<Azure Subscription Name>'
$resourceGroup = 'myresourcegroup'
$pubIpName = 'mypubip'
Get-AzureRmPublicIpAddress -ResourceGroupName $resourceGroup -Name $pubIpName
Look for something like this in what's returned from the script above:
DnsSettingsText: {
"Fqdn": "00000000-1111-2222-3333-444444444444.cloudapp.net"
}
The fqdn is what you'll use to setup your CNAME.