Intranet blocking internet connection - proxy
This is the scenario:
1) Linux installed with squid properly configured and working. Yesterday, internet suddenly stopped working;
2) If I unplug eth0 and pass eth1 to internet, the machine access the internet. If eth0 is plugged to intranet, internet stops again. However, intranet works with pings and SSHs;
3) If eth0 is plugged to the internet, I have no access;
4) I suspected if some administrator blocked the MAC address of eth0, but it is blocking internet access even when connected only to the intranet side. Changing the MAC address has not solved the problem either.
Currently I have either internet or intranet working. eth1 works with both. eth0 works with intranet, but blocks all internet access.
Any help is highly appreciated.