Common probably and I'm sure I've solved this before at another school but for the life of me can't figure it out this time!
We have a private IP range routed on to our County's larger private IP range. Web request go through an onsite proxy server on port 1080 and are then forwarded to another Countywide proxy server before reaching the wider Internet.
We are looking at investing in either Kindles or Android tablets and are having problems with entering proxy settings, or the lack of support for these settings.
So the solution is to set up a router on our network to route traffic from a new private range onto our existing private range and in the process transparently redirect port 80 requests to our proxy server.
Hopefully that makes sense.
Here's what I've done:
Set up a Hyper-V virtual machine with two NICs and installed CentOS 6.1 i386 minimal. Eth0 is on our existing range (10.96.22.100) and eth1 is on the new range (172.16.20.1)
Here are router setting's I've tried:
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat --flush
iptables -t nat --delete-chains
iptables -A FORWARD -i eth0 -o eth1 -j ACCEPT
iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT
iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 80 -j DNAT --to 10.96.22.5:1080
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables-save > /etc/sysconfig/iptables
service iptables stop
service iptables start
chkconfig iptables on
service iptables status
On the Kindle, the Android tab and my iPhone I've tried the following settings
but what we've done is make a separate transparent proxy that handles guest wireless and everything: iptables, squid, dns, dhcp is on one box so it's an isolated system. the two lan cards one is vlan for guest wireless, the other plugs into the router than connects to county.