Firewalls that are known to cause issues with Cisco VPN, and ASA remote phone solution
Model: All Models
Recommended workaround: Multipile solutions have been tried including putting the ASA in a DMZ, and disabling deep packet inspection. So far the only known resolution is to bypass the firewall completely by obtaining a static IP from the ISP, and statically addressing the public interface of the ASA5505. The public port then needs to be patched directly into the customers internet router.