Re: [SR-Users] R: Kamailio connection issue

4 Mar 2020

You have many problems,

1. You do not seem to have TCP keepalives setup. So idle TCP connections
may be disrupted, closed or reset by any router on the internet, forcing
SIP client to re-register. As a result many more tcp connections are
created by a single SIP end point then expected. You said you have 5K
active users with 8K connection limit, which is way too low. The limit
should be at least more then twice the active users (12.5K in your case). I
usually just set it to maximum i.e. 64K.

2. TCP connection life time of 3605 seconds is way too high. There will be
many many hack attempts on your server, some users will enter wrong
password, some users change their network (and thus need to re-register),
so allowing 3605 seconds life time for ALL of them is a HUGE mistake, and
you will run out of connection limit pretty quick. So keep the life time as
small as possible 5 or 10 seconds (approx. max time the server takes to
process sip register x 20 e.g. 250ms x 20 = 5000 ms = 5 seconds). Once the
SIP client successfully registers, you can increase the TCP life time using,

https://kamailio.org/docs/modules/4.4.x/modules/tcpops.html#tcpops.f.tcp_se…

3. Similarly setup TCP keepalives according to SIP Register success,

https://kamailio.org/docs/modules/4.4.x/modules/tcpops.html#tcpops.f.tcp_ke…
https://kamailio.org/docs/modules/4.4.x/modules/tcpops.html#tcpops.f.tcp_ke…

4. If average SIP packet processing time is too high e.g. due to slow db
connection for authentication etc. push notification setup, web queries
etc. then use ASYNC for all time consuming tasks. So TCP listener processes
get freed quickly and can process more new connections.

5. It's good to monitor and analyze TCP connection states and events,
especially when TCP connections closes and why? See the TCPOPS module for
more help.

Hope this helps.

On Wed, Mar 4, 2020 at 5:30 PM Tomas Zanet &lt;tzanet(a)came.com&gt; wrote:

...
  As you suggested I increased the debug level from -1
to 3 and I got this
 Kamailio log:

 Mar  4 15:40:21 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [io_wait.h:602]: io_watch_del(): DBG: io_watch_del (0xa20dc0, 3433,
 -1, 0x0) fd_no=2922 called

 Mar  4 15:40:21 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:4139]: handle_tcpconn_ev(): sending to child, events 1

 *Mar  4 15:40:21 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (30)*

 Mar  4 15:40:21 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3821]: send2child(): selected tcp worker 8 36(29409) for
 activity on [tls:X.X.X.X:5061], 0x7f482c2c2bc0

 Mar  4 15:40:21 server-xip-01 /usr/local/sbin/kamailio[29409]: DEBUG:
 <core> [tcp_read.c:1576]: handle_io(): received n=8 con=0x7f482c2c2bc0,
 fd=13

 Mar  4 15:40:21 server-xip-01 /usr/local/sbin/kamailio[29409]: DEBUG: tls
 [tls_server.c:197]: tls_complete_init(): completing tls connection
 initialization

 Mar  4 15:40:21 server-xip-01 /usr/local/sbin/kamailio[29409]: DEBUG: tls
 [tls_server.c:226]: tls_complete_init(): Using initial TLS domain
 TLSs<default> (dom 0x7f481b22ba50 ctx 0x7f481b6fbf20 sn [])

 Mar  4 15:40:21 server-xip-01 /usr/local/sbin/kamailio[29409]: DEBUG: tls
 [tls_domain.c:715]: sr_ssl_ctx_info_callback(): SSL handshake started

 Looking for this warning into the log, I realized that there are a lot of
 these messages:

 sudo tail -f /var/log/kamailio.log | grep "no free tcp receiver"

 Mar  4 15:40:23 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (20)

 Mar  4 15:40:23 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (20)

 Mar  4 15:40:23 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (21)

 Mar  4 15:40:23 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (20)

 Mar  4 15:40:23 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (21)

 Mar  4 15:40:24 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (14)

 Mar  4 15:40:24 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (15)

 Mar  4 15:40:24 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (16)

 Mar  4 15:40:24 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (16)

 Mar  4 15:40:24 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (16)

 Mar  4 15:40:24 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (17)

 Mar  4 15:40:24 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (17)

 Mar  4 15:40:24 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (17)

 Mar  4 15:40:24 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (16)

 Mar  4 15:40:24 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (17)

 Mar  4 15:40:24 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (18)

 Mar  4 15:40:24 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (18)

 Mar  4 15:40:24 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (18)

 Mar  4 15:40:24 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (18)

 Mar  4 15:40:24 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (18)

 Mar  4 15:40:24 server-xip-01 /usr/local/sbin/kamailio[29417]: DEBUG:
 <core> [tcp_main.c:3816]: send2child(): WARNING: no free tcp receiver,
 connection passed to the least busy one (18)

 …..

 ….

 As far as I know, I should increase the tcp_children parameter, right?.

 Now, it’s set to 16 but it’s pretty clear which is not enough. I increased
 it step by step till 48 but that’s still not enough.

 If I set it to 64 then Kamailio failed to start.

 What would you recommend for a server which has more or less 5K users?

 Many thanks.

 T.

 *Tomas Zanet*
 R&D Software Designer
 tzanet(a)came.com

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 *Da:* sr-users [mailto:sr-users-bounces@lists.kamailio.org] *Per conto di
 *Denys Pozniak
 *Inviato:* mercoledì 4 marzo 2020 15:00
 *A:* Kamailio (SER) - Users Mailing List &lt;sr-users(a)lists.kamailio.org&gt;
 *Oggetto:* Re: [SR-Users] Kamailio connection issue

 Hello!

 You can try to increase the debug printing level (like debug=2 or even
 debug=3) and check syslog when Kamailio gets stuck.

 ср, 4 мар. 2020 г. в 13:12, Tomas Zanet &lt;tzanet(a)came.com&gt;om>:

 Hi All,

 In these days I'm facing an issue or a misconfiguration, I don't know,
 with our remote apps (SIP clients) and our cloud server in which there's a
 Kamailio version 4.4.4.
 Sometimes our app takes some seconds (about 10-12sec) to connect to the
 Kamailio socket (sips on 5061) and our app is stuck on connect sytem call.

 To debug this behaviour I put a rule in the iptable like this:
 sudo iptables -I INPUT -p tcp -m tcp --dport 5061 -m state --state NEW  -j
 LOG --log-level 1 --log-prefix "New Connection "

 when everything goes well, there is one row which describes the new
 incoming connection Mar  4 07:08:40 server-xip-01 kernel: New Connection
 IN=eth0 OUT= MAC=bc:76:4e:20:1f:fb:e8:ed:f3:3a:52:41:08:00 SRC=X.X.X.X
 DST=Y.Y.Y.Y LEN=64 TOS=0x00 PREC=0x00 TTL=45 ID=0 DF PROTO=TCP SPT=15819
 DPT=5061 WINDOW=65535 RES=0x00 CWR ECE SYN URGP=0

 when our app gets stuck in the connect, there are many attempts and seems
 that Kamailio is not ready to accept this connection:
 Mar  4 07:11:54 server-xip-01 kernel: New Connection IN=eth0 OUT=
 MAC=bc:76:4e:20:1f:fb:e8:ed:f3:3a:52:41:08:00 SRC=X.X.X.X DST=Y.Y.Y.Y
 LEN=64 TOS=0x00 PREC=0x00 TTL=45 ID=0 DF PROTO=TCP SPT=52900 DPT=5061
 WINDOW=65535 RES=0x00 CWR ECE SYN URGP=0 Mar  4 07:11:54 server-xip-01
 kernel: New Connection IN=eth0 OUT=
 MAC=bc:76:4e:20:1f:fb:e8:ed:f3:3a:52:41:08:00 SRC=X.X.X.X DST=Y.Y.Y.Y
 LEN=64 TOS=0x00 PREC=0x00 TTL=45 ID=0 DF PROTO=TCP SPT=52900 DPT=5061
 WINDOW=65535 RES=0x00 SYN URGP=0 Mar  4 07:11:55 server-xip-01 kernel: New
 Connection IN=eth0 OUT= MAC=bc:76:4e:20:1f:fb:e8:ed:f3:3a:52:41:08:00
 SRC=X.X.X.X DST=Y.Y.Y.Y LEN=64 TOS=0x00 PREC=0x00 TTL=45 ID=0 DF PROTO=TCP
 SPT=52900 DPT=5061 WINDOW=65535 RES=0x00 SYN URGP=0 Mar  4 07:11:55
 server-xip-01 kernel: New Connection IN=eth0 OUT=
 MAC=bc:76:4e:20:1f:fb:e8:ed:f3:3a:52:41:08:00 SRC=X.X.X.X DST=Y.Y.Y.Y
 LEN=64 TOS=0x00 PREC=0x00 TTL=45 ID=0 DF PROTO=TCP SPT=52900 DPT=5061
 WINDOW=65535 RES=0x00 SYN URGP=0 Mar  4 07:11:55 server-xip-01 kernel: New
 Connection IN=eth0 OUT= MAC=bc:76:4e:20:1f:fb:e8:ed:f3:3a:52:41:08:00
 SRC=X.X.X.X DST=Y.Y.Y.Y LEN=64 TOS=0x00 PREC=0x00 TTL=45 ID=0 DF PROTO=TCP
 SPT=52900 DPT=5061 WINDOW=65535 RES=0x00 SYN URGP=0 Mar  4 07:11:56
 server-xip-01 kernel: New Connection IN=eth0 OUT=
 MAC=bc:76:4e:20:1f:fb:e8:ed:f3:3a:52:41:08:00 SRC=X.X.X.X DST=Y.Y.Y.Y
 LEN=64 TOS=0x00 PREC=0x00 TTL=45 ID=0 DF PROTO=TCP SPT=52900 DPT=5061
 WINDOW=65535 RES=0x00 SYN URGP=0 Mar  4 07:11:56 server-xip-01 kernel: New
 Connection IN=eth0 OUT= MAC=bc:76:4e:20:1f:fb:e8:ed:f3:3a:52:41:08:00
 SRC=X.X.X.X DST=Y.Y.Y.Y LEN=64 TOS=0x00 PREC=0x00 TTL=45 ID=0 DF PROTO=TCP
 SPT=52900 DPT=5061 WINDOW=65535 RES=0x00 SYN URGP=0 Mar  4 07:11:56
 server-xip-01 kernel: New Connection IN=eth0 OUT=
 MAC=bc:76:4e:20:1f:fb:e8:ed:f3:3a:52:41:08:00 SRC=X.X.X.X DST=Y.Y.Y.Y
 LEN=64 TOS=0x00 PREC=0x00 TTL=45 ID=0 DF PROTO=TCP SPT=52900 DPT=5061
 WINDOW=65535 RES=0x00 SYN URGP=0 Mar  4 07:11:58 server-xip-01 kernel: New
 Connection IN=eth0 OUT= MAC=bc:76:4e:20:1f:fb:e8:ed:f3:3a:52:41:08:00
 SRC=X.X.X.X DST=Y.Y.Y.Y LEN=64 TOS=0x00 PREC=0x00 TTL=45 ID=0 DF PROTO=TCP
 SPT=52900 DPT=5061 WINDOW=65535 RES=0x00 SYN URGP=0 Mar  4 07:12:00
 server-xip-01 kernel: New Connection IN=eth0 OUT=
 MAC=bc:76:4e:20:1f:fb:e8:ed:f3:3a:52:41:08:00 SRC=X.X.X.X DST=Y.Y.Y.Y
 LEN=64 TOS=0x00 PREC=0x00 TTL=45 ID=0 DF PROTO=TCP SPT=52900 DPT=5061
 WINDOW=65535 RES=0x00 SYN URGP=0 Mar  4 07:12:05 server-xip-01 kernel: New
 Connection IN=eth0 OUT= MAC=bc:76:4e:20:1f:fb:e8:ed:f3:3a:52:41:08:00
 SRC=X.X.X.X DST=Y.Y.Y.Y LEN=48 TOS=0x00 PREC=0x00 TTL=45 ID=0 DF PROTO=TCP
 SPT=52900 DPT=5061 WINDOW=65535 RES=0x00 SYN URGP=0 When it happens our app
 takes more than 10 sec to connect to the Kamailio socket.

 I tried to increase the children configuration parameter in the cfg file
 because I thought there were not enough tcp receiver but with no luck.
 Here are some configuration parameters:

 children = 16 // was 8 before found this issue

 # life time of TCP connection when there is no traffic # - a bit higher
 than registration expires to cope with UA behind NAT
 tcp_connection_lifetime=3605

 open_files_limit=8192

 tcp_max_connections=8192
 tls_max_connections=8192

 Here is the output of the ulimit command:
 ulimit -a
 core file size          (blocks, -c) 0
 data seg size           (kbytes, -d) unlimited
 scheduling priority             (-e) 0
 file size               (blocks, -f) unlimited
 pending signals                 (-i) 31393
 max locked memory       (kbytes, -l) 64
 max memory size         (kbytes, -m) unlimited
 open files                      (-n) 65535
 pipe size            (512 bytes, -p) 8
 POSIX message queues     (bytes, -q) 819200
 real-time priority              (-r) 0
 stack size              (kbytes, -s) 8192
 cpu time               (seconds, -t) unlimited
 max user processes              (-u) 31393
 virtual memory          (kbytes, -v) unlimited
 file locks                      (-x) unlimited
 In the kamailio log file I don't see anything wrong, I don't see messages
 like "[tcp_main.c:3913]: handle_new_connect(): maximum number of tls
 connections exceeded".

 Here is the output of kamctl ps command
 Process::  ID=0 PID=11725 Type=main process - attendant
 Process::  ID=1 PID=11727 Type=udp receiver child=0 sock=
 10.208.194.26:5061
 Process::  ID=2 PID=11728 Type=udp receiver child=1 sock=
 10.208.194.26:5061
 Process::  ID=3 PID=11729 Type=udp receiver child=2 sock=
 10.208.194.26:5061
 Process::  ID=4 PID=11730 Type=udp receiver child=3 sock=
 10.208.194.26:5061
 Process::  ID=5 PID=11731 Type=udp receiver child=4 sock=
 10.208.194.26:5061
 Process::  ID=6 PID=11732 Type=udp receiver child=5 sock=
 10.208.194.26:5061
 Process::  ID=7 PID=11733 Type=udp receiver child=6 sock=
 10.208.194.26:5061
 Process::  ID=8 PID=11734 Type=udp receiver child=7 sock=
 10.208.194.26:5061
 Process::  ID=9 PID=11735 Type=udp receiver child=8 sock=
 10.208.194.26:5061
 Process::  ID=10 PID=11736 Type=udp receiver child=9 sock=
 10.208.194.26:5061
 Process::  ID=11 PID=11737 Type=udp receiver child=10 sock=
 10.208.194.26:5061
 Process::  ID=12 PID=11738 Type=udp receiver child=11 sock=
 10.208.194.26:5061
 Process::  ID=13 PID=11739 Type=udp receiver child=12 sock=
 10.208.194.26:5061
 Process::  ID=14 PID=11740 Type=udp receiver child=13 sock=
 10.208.194.26:5061
 Process::  ID=15 PID=11741 Type=udp receiver child=14 sock=
 10.208.194.26:5061
 Process::  ID=16 PID=11742 Type=udp receiver child=15 sock=
 10.208.194.26:5061
 Process::  ID=17 PID=11743 Type=slow timer
 Process::  ID=18 PID=11744 Type=timer
 Process::  ID=19 PID=11745 Type=secondary timer
 Process::  ID=20 PID=11746 Type=MI FIFO
 Process::  ID=21 PID=11747 Type=USRLOC Timer
 Process::  ID=22 PID=11748 Type=USRLOC Timer
 Process::  ID=23 PID=11749 Type=USRLOC Timer
 Process::  ID=24 PID=11750 Type=USRLOC Timer
 Process::  ID=25 PID=11751 Type=ctl handler
 Process::  ID=26 PID=11752 Type=RTIMER SEC EXEC
 Process::  ID=27 PID=11753 Type=TIMER NH
 Process::  ID=28 PID=11754 Type=tcp receiver (generic) child=0
 Process::  ID=29 PID=11755 Type=tcp receiver (generic) child=1
 Process::  ID=30 PID=11756 Type=tcp receiver (generic) child=2
 Process::  ID=31 PID=11757 Type=tcp receiver (generic) child=3
 Process::  ID=32 PID=11758 Type=tcp receiver (generic) child=4
 Process::  ID=33 PID=11759 Type=tcp receiver (generic) child=5
 Process::  ID=34 PID=11760 Type=tcp receiver (generic) child=6
 Process::  ID=35 PID=11761 Type=tcp receiver (generic) child=7
 Process::  ID=36 PID=11762 Type=tcp receiver (generic) child=8
 Process::  ID=37 PID=11763 Type=tcp receiver (generic) child=9
 Process::  ID=38 PID=11764 Type=tcp receiver (generic) child=10
 Process::  ID=39 PID=11765 Type=tcp receiver (generic) child=11
 Process::  ID=40 PID=11766 Type=tcp receiver (generic) child=12
 Process::  ID=41 PID=11767 Type=tcp receiver (generic) child=13
 Process::  ID=42 PID=11768 Type=tcp receiver (generic) child=14
 Process::  ID=43 PID=11769 Type=tcp receiver (generic) child=15
 Process::  ID=44 PID=11770 Type=tcp main process

 Can anyone address me to find out this happens, please?
 Please let me know if you need further information...

 Thanks in advance,
 Best Regards
 Tomas

 Tomas Zanet
 R&D Software Designer
 tzanet(a)came.com
 CAME S.p.A.

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 --

 BR,

 Denys Pozniak

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Re: [SR-Users] R: Kamailio connection issue