TCP Settings

Qualcomm® Package Manager servers firewalls have a connection timeout of 1 hour set. This means that if we do not receive a packet, in either direction for one hour, that the connection is closed.

Similarly on the Apache side, our timeout value is 300000 seconds (3.47 days), which is essentially never.

Please check to see what your network timeout value is, or if an interface is failing. Similarly, depending on the kernel version, the default kernel TCP timeout is 20 seconds. Your network administrators may want to try setting this to a higher number.

Below are the relevant TCP settings:

net.ipv4.tcp_syn_retries = 5
net.ipv4.tcp_keepalive_time = 7200
net.ipv4.tcp_keepalive_probes = 9
net.ipv4.tcp_retries1 = 3
net.ipv4.tcp_fin_timeout = 60
sunrpc.tcp_fin_timeout = 15

tcpkeepaliveprobes: Number of KEEPALIVE probes tcp sends out, until the server decides that the connection is broken.

tcpkeepalivetime: This value shows how often tcp sends out KEEPALIVE messages. The default is 7200 (2 hours).

tcpsynretries: Number of times initial SYNs for a TCP connection attempt will be retransmitted. This value should not be more than 255. This is only the timeout for outgoing connections.

tcp_retries1: This defines how often an answer to a TCP connection request is retransmitted before it gives up. This is only the timeout for incoming connections.

tcpfintimeout: The length of time (in seconds) TCP takes to receive a final FIN before the socket is always closed. This is required to prevent DoS attacks