Contents

Problem

Symptoms: When using Putty to tunnel (CONNECT) through the WSA, you receive "Proxy error: 407 Proxy Authentication Required", even after including a username / password in the Putty configuration.

Environment: Cisco Web Security Appliance (WSA), all versions of AsyncOS

Solution

Putty only supports HTTP Basic authentication. It does NOT support NTLM authentication. If the WSA is configured for NTLM authentication only, Putty will return this error message.

If WSA is configured to use 'NTLMSSP or Basic' authentication scheme, then authentication should work properly.

On AsyncOS versions 7.x and above, the 'NTLMSSP or Basic' authentication scheme is configured in Identities under GUI --> Web Security Manager --> Identities --> "Define Members by Authentication" section.