# Limitations of Sidewinder Proxies

These limitations apply to Sidewinder Proxies.

- Sidewinder Proxies are not supported with legacy role-specific licenses. An Security Engine license is required.
- Only the Engine/VPN role is supported.
- On Engine Clusters, connection failover is not supported.
- Master Engines only support advanced Sidewinder Proxy settings for the Virtual Engines that they host. Master Engines cannot use Sidewinder Proxies for their own traffic.
- Sidewinder Proxies can be used with both IPv4 and IPv6 traffic. However, they do not support translation between IPv4 and IPv6, or tunneling of IPv4 or IPv6 traffic in an IPv6 or IPv4 connection.
- Sidewinder Proxies do not support multicast traffic.
- In the Engine Policy, you cannot place Access rules that match based on Endpoint Context Agent information above Access rules for Sidewinder Proxies.
- You cannot use McAfee Threat Intelligence Exchange (TIE) file reputation with Sidewinder Proxies. If the File Filtering Policy uses these file reputation scans, they are ignored for traffic that uses Sidewinder Proxies. When you restrict file types with file filtering, the action specified for the Action When No Scanners Are Available option determines whether the file transfer is allowed or blocked if no other scanners are available.