What is NTLM 407 proxy authentication required?

What is proxy authenticate?

I would like to know this.

Basically when you are behind a load balancer it redirects all of the outgoing traffic through the load balancer itself. So even though the traffic is leaving your machine, it is going through the load balancer which is going to respond with a 302 status code in addition to other stuff. This basically means that the incoming traffic must verify the host name and authorization.

The typical case of this happening is with an SSL based load balancer. If the client request goes out to your webserver or other servers in the system (the web server being an example) it would go directly back out to the destination server. However in these cases they may change from time to time.

Usually what you would want is to configure your browser and other software that communicates with the load balancer to set the http headers so that the load balancer does not have to do any verification. In addition to this the load balancer will do some additional caching in order to provide faster response times.

Is NTLM authentication still used?

I just found out that a number of websites I visit have a "NTLM" authentication method, where I'm asked to enter a username and password (using Microsoft's browser based authentication method). Does anybody know if it's still used or is it something that was phased out years ago? Cheers. Paul. NTLM is an old protocol, but it is not dead. It is used by many sites for backwards compatibility and legacy support. For example, NTLM authentication is supported by the Google Web Search engine.

Google even allows you to disable NTLM for specific domains if you want to. Wikipedia also has a page on NTLM. The fact that it's been around since the 1990s means that it's still in use, though it has been phased out for new sites. You may want to check the history of your own site.