I have the same problem, and not familiar with Linux. Is there a way that I can process the setting from WebAdmin or could you provide a step-by-step Linux operation instruction? Many Thanks.
There is no way to change the address via WebAdmin - personally I think that there is no need to change it since Astaro doesn't allow to configure roles - so the firewall admin is automatically cache manager too. I would be careful with Xeno's advise, settings in '<>' are place holders and will be replaced by the real values after you have enabled the proxy.
simple quickstart guide.
Login via SSH using loginuser, Putty is an excellent Windows SSH client. Next step is to mutate to root - simply enter 'su -' and give root's password. Change directory 'cd' to /var/chroot-squiid/etc. You have the choice between two editors to open squid.conf-default first is 'vi' which is not very comfortable for linux beginners the other one is 'joe'. Within 'joe' you get help by pressing 'CTRL + K+ H'.....