Smoothwall Express 3.0 NAT a NAT?
I am trying to set up a Smoothwall Express 3.0 proxy to allow my school network to connect to the internet supplied by our county council. The new setup is to replace an old Cobalt Qube that has failed after 9 years continuous service (PSU problem) The old proxy used Squid and with the exception of occasional problems caused by log files accumulating faster than the cron job to rotate them was very reliable.
The academic network (270+ computers) is a Windows 2003 domain. Network mask 255.255.0.0. we use the 10.0.xxx.xxx IP range. Almost all the computers gain their addresses via DHCP. A group policy sets the proxy settings used by IE to connect via 10.0.0.1 using port 3128. The county supply us with a single outward facing static IP address 172.xxx.xxx.xxx, and the addresses of primary and secondary DNS servers. We have to use port 3128 to connect to their smoothwall proxy server c***.xxx.sch.uk.
Physically the smoothwall server lies between the school network and the county WAN connected via a pair of NICs
If as an administrator I manually enter c***.xxx.sch.uk. and port 3128 into the IE LAN settings I can connect to the internet. This must be going through the smoothwall proxy as there is no other physical path it can take. But no matter what settings I try in the smoothwall configuration I cannot get machines to connect via 10.0.0.1:3128.
I would welcome any suggestions as how to proceed.