Re: ipv4 connection problems
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On Mon, Mar 14, 2005 at 04:35:00PM -0800, Matthew Dillon wrote:
> Peter. I did some webbench tests to try to reproduce the problem, and
> I found two limitations that might have something to do with it. I=
=20
> would like you to check these two things while your machine is not re=
sponding
> to apache requests.
>=20
> If it turns out to be one of these two things, I don't think your iss=
ue is
> related to the firefox or opera issue.
>=20
> You could be:
>=20
> (1) Running out of sockets.
> (2) Running out of tcp ports.
>=20
>=20
> (1) Running out of sockets. Any server that accepts connections wil=
l wind
> up with the socket in a TIME_WAIT state for 2 minutes after the connecti=
on
> closes.
>=20
> If your kern.ipc.maxsockets is, say, 5000, then 5000 / 120 seconds =3D=3D
> only 33 connections per second before you run out of sockets.
>=20
> (2) Running out of tcp ports. If you are getting a lot of connection=
s from
> the SAME IP address, the originating machine (the client you were using
> to test connections to your ftp server in this case) may run out of TCP
> ports or may start reusing ports that are still in TIME_WAIT on the=20
> target machine.=20
>=20
> 2 minutes to timeout it would only take 33 connections per second to run
> out of ports. But ONLY if all the connections are coming from the same =
IP
> address (since the limitation is based on the {ipaddress,port} tuple, not
> just the {port}).
>=20
> How do you tell? When you hit this situation, do this:
>=20
> sysctl net.inet.ip.portrange
> sysctl kern.ipc.maxsockets
> netstat -tn | wc -l
> netstat -tn | fgrep TIME_WAIT | wc -l
> netstat -m
>=20
> And that should tell you (and us) what is going on.
>=20
> If that turns out to be the case, then it probably is not related to =
the
> Opera/FireFox delay issue.
>=20
Right after I had a hung telnet:
box:~% sysctl net.inet.ip.portrange
net.inet.ip.portrange.lowfirst: 1023
net.inet.ip.portrange.lowlast: 600
net.inet.ip.portrange.first: 1024
net.inet.ip.portrange.last: 5000
net.inet.ip.portrange.hifirst: 49152
net.inet.ip.portrange.hilast: 65535
box:~% sysctl kern.ipc.maxsockets
kern.ipc.maxsockets: 12328
box:~% netstat -tn | wc -l
229
box:~% netstat -tn | fgrep TIME_WAIT | wc -l
25
box:~% netstat -m
1024/2278/26624 mbufs in use (current/peak/max):
1024 mbufs allocated to data
920/1306/6656 mbuf clusters in use (current/peak/max)
3181 Kbytes allocated to network (15% of mb_map in use)
0 requests for memory denied
0 requests for memory delayed
0 calls to protocol drain routines
Peter
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