Unable to browse external websites.
Error " http 1.1 gateway timeout" on Secure Web.
VPN mode : Full VPN

Internal websites work fine.

• Tried to access google from NetScaler which failed.
• Able to ping the URL by IP address.
• Name servers show as down, tried adding address record manually on NS which did not fix the issue.
• Changed the Split DNS from both to local, no effect.
• Checked the traces and Secure Logs, identified the issue with DNS resolution.
• ICMP traffic was blocked on default gateway, which was allowed later on and DNS server started showing as UP.
• Enabled ICMP for default gateway: This fixed the issue.
• External website started working as expected.

Problem Cause