[squid-users] Zyxel USG20 and Squid 3.3

[wn48z]

Since long time I'm trying to upgrade from Squid 2.7 to 3.x but every
try has failed up to now.

I use a ZyXel USG 20 firewall with LAN and DMZ Zone. The Squid proxy
server (MySquid) is running inside the DMZ with a single IP. The Zyxel
USG 20 has a option for a "HTTP Redirect". This is defined like:

Forward all HTTP Request from LAN to WAN to MySquid Port 3128.

On MySquid, a Squid 2.7 stable version is running with this setting:

http_port 3128 transparent

It works fine - any HTTP requests from LAN goes through the MySquid Proxy.

When I upgrade from 2.7 to 3.3 with some small modifications to the
default configuration from Squid 3.3:

ACL settings like before
http_Port 3128 intercept

I always get a "null size" / Bad Gateway 502 message in any browser
inside the LAN for all HTTP internet pages. If I change the setting to:

http_port 3128

(without intercept) and use a manual browser proxy settings
(MySquid:3128) - the access works through the new proxy server like before.

But that is no option - I can't and will not define manual proxy
settings for any client in the LAN :(

I can post more detailed informations - debug logs, settings files -
just ask what you need

Thanks, Martin