What is SOCKS?

SOCKS is an open industry-standard protocol advanced by the authenticated Firewall Traversal working group of the IETF (Internet Engineering Task Force). It defines a protocol, which allows TCP applications to access firewalls in a secure and controlled manner, gaining authenticated access through that server to an external network. It can be straightway used to construct a firewall ona TCP/IP based server.

There a number of products based on SOCKS specifications such as Auto SOCKS available in the market. The main problem with SOCKS is that it lacks transparency to software developers and users. A number of companies including IBM, DEC, Cyber guard etc. have commercial firewall products deploying the SOCKS protocol.

Use of SOCKS
SOCKS is a networking middleware: a circuit level gateway, acting as a proxy and is placed at the session layer to mediate client/server connections. It can be used to connect or establish connections between two hosts and perform transactions on an intranet or the Internet. Since it functions at the lower layer than application layer, it is clearly application-independent.
Implementation requires a change to all existing client-based software so that all of them use the SOCKS libraries. This process of changing the client code is known as "socksifying". This could be extremely cumbersome since it is also expected that at both side similar level of programming should be available since the entire process takes at the sessions layer.
Socks combine powerful features of circuit-level proxies without the programming overhead of traditional application level firewalls.