This is another directive that controls the way Squid waits for ICP/HTCP replies. Squid marks each of its peers as either dead (down) or alive (up). Squid uses ICP/HTCP replies (and other techniques) to determine a peer’s state. If Squid doesn’t receive any replies for the time specified by dead_peer_timeout , the peer is declared dead.
When a peer is declared dead, Squid continues to send it ICP/HTCP queries. However, it doesn’t expect to receive replies. That is, a dead peer isn’t included in the algorithm that decides when all ICP replies have been received. As soon as Squid receives an ICP/HTCP reply from a dead peer, its state is changed to alive.
Squid tends to be paranoid about the state of its peers. Additionally, Squid doesn’t proactively monitor the peers when there are no client requests. When Squid has no occasion to send ICP/HTCP queries, the state of the peer is unknown. If Squid doesn’t send any ICP/HTCP queries for an amount of time longer than dead_peer_timeout, Squid treats the peer as dead.
dead_peer_timeout 10 seconds
dead_peer_timeout 30 seconds
icp_port, htcp_port, icp_query_timeout