Im using the latest version of Avast free antivirus and it fails to auto update behind the squid proxy. If i update it manually it works. There is no restriction from the squid server to block avast. Since the manual update works im confused as to what the reason behind this. Please help me.
You either need to enter the Squid Proxy settings in the avastUI, Settings, Updates, Proxy Settings, Specify proxy server and input any authentication settings (see image, click to expand).
My guess is that it is on the default setting, Auto detect (use Internet Explorer settings), if so you would need to have the Squid Proxy settings in IE:
If you have them setup in IE then for some reason avast is unable to access them in IE.
If not you would either need to set IE to use Squid Proxy or (my preferred option) to manually set the Squid Proxy settings in the avast update settings.