Cisco AnyConnect VPN Fails to Connect on Xfinity XB8 Router Despite Normal Network Function and Successful Hotspot Connection

Issue Summary:

I’m unable to establish a VPN connection using Cisco AnyConnect Secure Mobility Client while connected to my Xfinity XB8 router. The VPN client times out or fails to connect when using my home Wi-Fi network, but works immediately when using a mobile hotspot or other networks. This indicates the issue is specific to my Xfinity gateway or its configuration.

Troubleshooting Performed:

• IPv6: Disabled/tested — no change.

• Firewall: Set to Low (minimum filtering) — no change.

• Wi-Fi Band Steering: Disabled; 2.4 GHz and 5 GHz bands are split — no change.

• WPA Security Type: Set to WPA2 (AES) — no change.

• Device/VPN Software: Confirmed working properly; connects successfully through a hotspot.

• Port Blocking: Verified UDP 443 is open — no change.

Observed Behavior:

• VPN connection fails or hangs during the “Establishing secure connection” phase.

• All other internet services (browsing, streaming, etc.) function normally.

• The issue occurs across multiple devices using the XB8 gateway.

Request:

Please investigate whether the XB8 firmware or configuration could be blocking or interfering with VPN passthrough or Cisco AnyConnect traffic (e.g., SSL VPN over TCP 443 or DTLS over UDP 443). I’d appreciate confirmation that IPSec, SSL, and DTLS passthrough are enabled and not restricted by default on the XB8.