Upstream proxy

cache_peer - Proxies can also communicate with each other. This section explains the concatenation of proxies among each other.

Proxy address forwarding:

request_header_access - With this option enabled, the HTTP version, address information:port and Squids version number will be transmitted from the local to the upstream proxy, this information is employed over the HTTP VIA field from the header. In combination with the TRACE-method this function can be useful for troubleshooting in a proxy compound.

Client IP address forwarding:

replay_header_access - This option adds the LAN IP address of the client by the use of HTTP X-FORWARDED-For to the HTTP header.

Username forwarding:

request_header_access - With this option, the username of the user will be transferred. The Proxy authentication must be activated. This can be useful for logging purposes or for the user ACL on the remote proxy.

No connection oriented authentication forwarding:

replay_header_access - Disables authentication methods such as e.g. the NT LAN Manager (Single Sign-On) or Kerberos.

Upstream proxy (host:port)

cache_peer - In here the local proxy IP address:port can be connected with an external upstream proxy via HTTP or HTTPS connection. If no port is specified, the default port 80 will be used.

Upstream username:

login - If the upstream proxy is configured with an authentication, you can enter your user name here.

Upstream password:

login - If the upstream proxy uses password authentication, the password can be filled up in this section.

Default Syntax:
cache_peer hostname/IP parent 3128 3130 default no-query

"hostname" is the IP or the domain of the neighboring proxy (cache_peer).
"parent" are higher-level proxies of further connections. These can also deliver objects from their cache. There are two groups of proxies 1. Parents and 2. Siblings, while the latter group is equal staged to the requesting proxy.
"3128" is the port where the neighbor proxy is listening.
"3130" is the ICP default port, where the availability of objects will be requested from other Squid proxies.
"no-query" disables ICP requests to the neighbor proxy

Next configuration section

Back to proxy main page

Additional links

http://www.squid-cache.org/Doc/config/cache_peer/