Network tunning
scuba at centroin.com.br
scuba at centroin.com.br
Wed Mar 29 16:04:23 UTC 2006
Hi all,
I need some help to fine tune a mail server.
The machine is running (Fbsd 5.4) for a long time, but I'm seeing
too many connections droped in sendmail log, and some users complains
about timeout connecting to smtp port.
From the handbook I increased the kern.ipc.somaxconn to 1024 as
sugested. Using "ps axH" shows about 350 processes.
With "netstat -s -p tcp" worrys me the value of "listen queue
overflows", is it normal?
Bellow is the full output of netstat.
What else can I use to track the problem?
Thank you,
- Marcelo Souza
tcp:
299940903 packets sent
170887610 data packets (2229408012 bytes)
3195422 data packets (2540945914 bytes) retransmitted
122892 data packets unnecessarily retransmitted
9 resends initiated by MTU discovery
97048877 ack-only packets (7662921 delayed)
0 URG only packets
92888 window probe packets
24780412 window update packets
4041857 control packets
246506831 packets received
105676020 acks (for 1375023355 bytes)
12944539 duplicate acks
12456 acks for unsent data
72749271 packets (14818446 bytes) received in-sequence
8337796 completely duplicate packets (2516522316 bytes)
1814433 old duplicate packets
43730 packets with some dup. data (19627001 bytes duped)
56071043 out-of-order packets (3456612566 bytes)
2666 packets (3197931 bytes) of data after window
21 window probes
2895146 window update packets
60090 packets received after close
4802 discarded for bad checksums
1 discarded for bad header offset field
0 discarded because packet too short
972406 connection requests
2193450 connection accepts
379044 bad connection attempts
3508 listen queue overflows
15310 ignored RSTs in the windows
3103565 connections established (including accepts)
3166854 connections closed (including 337144 drops)
2617462 connections updated cached RTT on close
2658065 connections updated cached RTT variance on close
1857871 connections updated cached ssthresh on close
62026 embryonic connections dropped
94220002 segments updated rtt (of 81339570 attempts)
2752038 retransmit timeouts
42108 connections dropped by rexmit timeout
106133 persist timeouts
1378 connections dropped by persist timeout
49366 keepalive timeouts
705 keepalive probes sent
48657 connections dropped by keepalive
5490574 correct ACK header predictions
58517171 correct data packet header predictions
2363634 syncache entries added
665160 retransmitted
546143 dupsyn
0 dropped
2193450 completed
9240 bucket overflow
0 cache overflow
23559 reset
133854 stale
3508 aborted
0 badack
52 unreach
0 zone failures
0 cookies sent
33 cookies received
286560 SACK recovery episodes
586050 segment rexmits in SACK recovery episodes
816504390 byte rexmits in SACK recovery episodes
2640912 SACK options (SACK blocks) received
43198533 SACK options (SACK blocks) sent
0 SACK scoreboard overflow
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