This directive tells Squid how long to wait when trying to connect to an origin server. After this amount of time, Squid gives up and tries another location or returns an error to the user. Your operating system’s TCP implementation has its own connection timeout. If the TCP timeout occurs before connect_timeout, Squid creates a new TCP connection and tries again.
connect_timeout 2 minutes
connect_timeout 30 seconds
peer_connect_timeout, read_timeout, write_timeout, request_timeout, pconn_timeout, minimum_retry_timeout