Chapter 1 What’s New for FortiOS 5.2.1 : WAN Optimization, Web Cache, and Explicit Proxy : Explicit Web Proxy SOCKS services support for TCP and UDP traffic
  
Explicit Web Proxy SOCKS services support for TCP and UDP traffic
You can now configure Web Proxy services to allow UDP traffic as well as TCP traffic to be accepted by the SOCKS proxy. Previously, the web proxy would only accept TCP SOCKS traffic.
Web proxy services can be configured in the CLI.
Syntax
Use the following command to create a custom service for UDP traffic over the SOCKS proxy:
config firewall service custom
edit <name>
set explicit-proxy enable
set category Web\ Proxy
set protocol SOCKS-UDP
set tcp-portrange 8080-8080
end
end
The option to create a custom service for TCP traffic over the SOCKS proxy has also changed. For example, use the following command to create a custom service for TCP traffic over the SOCKS proxy:
config firewall service custom
edit <name>
set explicit-proxy enable
set category Web\ Proxy
set protocol SOCKS-TCP
set tcp-portrange 80-80
end
end