Assin Em 22/11/2015 16:25, Eliezer Croitoru escreveu:
Hey Andre,
There are couple things to the picture.
It's not only squid that is the "blame".
It depends on what your OS tcp stack settings are.
To verify couple things you can try to use the netstat tool.
run the command "netstat -nto" to see what is the timers status.
You can then see how long will a new connection stay in the
established state.
It might be the squid settings but if the client is not there it could
be because of some tcp tunable kernel settings.
Hi Eliezer and Amos,
my kernel is a regular Debian Jessie kernel using the following tcp values.
tcp_keepalive_time: 7200
tcp_keepalive_intvl: 25
tcp_keepalive_probes: 9
tcp_retries1: 3
tcp_retries2: 15
tcp_fin_timeout: 60
So in my understanding the longest timeout is set to 2 hours and a few
minutes for keepalive connections.
Today I monitored file descriptors 23 and 24 on my box during 5 hours
and lsof always showed:
squid 6574 proxy 23u IPv6 5320944
0t0 TCP 172.16.10.22:3126->192.168.90.35:34571 (CLOSE_WAIT)
squid 6574 proxy 24u IPv6 5327276
0t0 TCP 172.16.10.22:3126->192.168.89.236:49435 (ESTABLISHED)
while netstat always showed:
tcp6 1 0 172.16.10.22:3126 192.168.90.35:34571
CLOSE_WAIT 6574/(squid-1) off (0.00/0/0)
tcp6 0 0 172.16.10.22:3126 192.168.89.236:49435
ESTABLISHED 6574/(squid-1) off (0.00/0/0)
The "off" flag in netstat output tells that for these sockets keepalive
and retransmission timers are disabled.
Right now netstat shows 15,568 connections on squid port 3126 and only
107 have timer set to a value other than "off".
I read that connections that are in CLOSE_WAIT state don't have any tcp
timeout, it's Squid that must close the socket.
About the connections in ESTABLISHED state, I monitored the connection
to mobile device 192.168.89.236 using "tcpdump -i eth2 -n host
192.168.89.236" during 2 hours and a half.
Tcpdump didn't record any packet and netstat is still displaying:
tcp6 1 0 172.16.10.22:3126 192.168.90.35:34571
CLOSE_WAIT 6574/(squid-1) off (0.00/0/0)
tcp6 0 0 172.16.10.22:3126 192.168.89.236:49435
ESTABLISHED 6574/(squid-1) off (0.00/0/0)
So unfortunately I still don't understand why Squid or the kernel don't
close these sockets.
Regards,
André
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