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Strange issue Call Drop every 32 sec - please suggest WHY?

Discussion in '3CX Phone System - General' started by vinzer, Sep 28, 2009.

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  1. vinzer

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    Hello all,

    We are testing version 7 of the Phone System here. We have office with internal extensions plus few external extensions.
    Internal extensions works perfect. There is very strange issue with external ones.
    Assume there are two external extensions. Both are in the same city. Both external extensions have firewalls (routers Linksys WRT54), on both routers no single port is forwarded to phone extensions.
    Extension number one is on the same internet provider - cable. Extension number two is on different DSL provider.
    Extensions number one has phone Linksys sipura, extensions number two has Linksys PAP2T adapter and regular phone.
    Now strange things starts: Extension number one which is on the same cable internet provider works perfect and does not required STUN server !!! It is strange since it is behind the firewall which is completely closed and it still able to send its own EXTERNAL IP to the Phone system's server. Maybe this is because this extension is with the same Internet provider ?

    Extension number two, which is on different internet provider require STUN server and NAT enabled, otherwise we have only one way communication. On its firewall also no single port is opened.
    When using STUN and NAT there are no problem with second extension except every 30-32 sec call is dropped. But only when this extension is calling to the office. When from office we call to this extension no call drop. No ACK received ... bla bla bla. I understand that I have to open and forward port 5060 both TCP and UDP to second extension's IP probably. But than WHY EXTENSION NUMBER one, which has firewall CLOSED is able to receive ACK from server and does not drop connection ??? I can not understand this at all.

    Thank you.
    Vlad
     
  2. peterbunn

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    Re: Very strange issue - please suggest WHY?

    Have you tried using the 3cx tunnel?
     
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  3. discovery1

    discovery1 Member

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    Re: Very strange issue - please suggest WHY?

    It could be that phone number 1 supports UPNP and the firewall is also enabled for UPNP as well.
     
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  4. vinzer

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    Re: Very strange issue - please suggest WHY?

    I did not try to use tunneling and I prefer to stay away from tunneling since there is no PC which is always running at the remote location.
    UPNP - hmm, what does it mean that the phone number 1 supports it. You mean that the phone on extension 1 support UPNP and router supports it as well ? Hmm maybe.
    Do you know if Linksys PAP2T adapter supports UPNP ? I will check if the router on extension 2 supports UPNP. I know it is Linksys WRT54 router.
     
  5. vinzer

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    Re: Very strange issue - please suggest WHY?

    I am still confused :( Today I've tried to work on external extension 310. I tried to forward port 5060 TCP and UDP to it, tried to forward 9000-9049 ports. It still disconnects after 32 seconds. I am almost giving up. Please sugest me where is the problem. Below is the log of the call from extension 310 to 303 and it disconnects after 32 seconds.
    I assume I am missing some part of the information excahnge since there is ACK Not received, means at some point it should present in the log ?
    ------------------------------------------------------------------------------------------------------------------
    23:34:37.875 [CM503008]: Call(4): Call is terminated

    23:34:37.875 [CM503008]: Call(4): Call is terminated
    23:34:37.875 [CM503008]: Call(4): Call is terminated
    23:34:37.343 [CM503020]: Call(4): ACK is not received

    23:34:05.843 [CM503007]: Call(4): Device joined: sip:303@192.168.0.113:5060

    23:34:05.234 [CM503007]: Call(4): Device joined: sip:310@174.91.207.28:5060

    23:34:05.234 [CM505001]: Ext.303: Device info: Device Identified: [Man: Linksys;Mod: SPA Series;Rev: General] Capabilities:[reinvite, no-replaces, able-no-sdp, recvonly] UserAgent: [Linksys/PAP2T-5.1.6(LS)] Transport: [sip:192.168.0.51:5060]
    23:34:05.234 [CM503002]: Call(4): Alerting sip:303@192.168.0.113:5060

    23:33:54.453 [CM503024]: Call(4): Calling Ext:Ext.303@[Dev:sip:303@192.168.0.113:5060]

    23:33:54.437 [CM503004]: Call(4): Route 1: Ext:Ext.303@[Dev:sip:303@192.168.0.113:5060]

    23:33:53.843 [CM503010]: Making route(s) to <sip:303@httcanada.dyndns.org>

    23:33:53.843 [CM505001]: Ext.310: Device info: Device Identified: [Man: Linksys;Mod: SPA Series;Rev: General] Capabilities:[reinvite, no-replaces, able-no-sdp, recvonly] UserAgent: [Linksys/PAP2T-5.1.6(LS)] Transport: [sip:192.168.0.51:5060]
    23:33:53.515 [CM503001]: Call(4): Incoming call from Ext.310 to <sip:303@httcanada.dyndns.org>
    -----------------------------------------------------------------------------------------------------------------------------------


    Below is the log when extension 303 cals to extension 310 and everything is OK, call does not disconnect by it self, it has been disconnected by extension 303

    ----------------------------------------------------------------------------------------------------------------------

    23:43:09.359 [CM503008]: Call(5): Call is terminated
    23:43:09.265 [CM503008]: Call(5): Call is terminated

    23:42:14.875 [CM503007]: Call(5): Device joined: sip:310@174.91.207.28:5060

    23:42:14.671 [CM503007]: Call(5): Device joined: sip:303@192.168.0.113:5060

    23:42:14.671 [CM505001]: Ext.310: Device info: Device Identified: [Man: Linksys;Mod: SPA Series;Rev: General] Capabilities:[reinvite, no-replaces, able-no-sdp, recvonly] UserAgent: [Linksys/PAP2T-5.1.6(LS)] Transport: [sip:192.168.0.51:5060]

    23:42:14.671 [CM503002]: Call(5): Alerting sip:310@174.91.207.28:5060

    23:42:11.343 [CM503024]: Call(5): Calling Ext:Ext.310@[Dev:sip:310@174.91.207.28:5060]

    23:42:11.328 [CM503004]: Call(5): Route 1: Ext:Ext.310@[Dev:sip:310@174.91.207.28:5060]

    23:42:10.750 [CM503010]: Making route(s) to <sip:310@192.168.0.51>

    23:42:10.750 [CM505001]: Ext.303: Device info: Device Identified: [Man: Linksys;Mod: SPA Series;Rev: General] Capabilities:[reinvite, no-replaces, able-no-sdp, recvonly] UserAgent: [Linksys/PAP2T-5.1.6(LS)] Transport: [sip:192.168.0.51:5060]
    23:42:10.421 [CM503001]: Call(5): Incoming call from Ext.303 to <sip:310@192.168.0.51>
    ----------------------------------------------------------------------------------------------------------------------------
    Please suggest me what elso to try.
     
  6. vinzer

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    Re: Very strange issue - please suggest WHY?

    Also I have STUN Server at the 3CX Server end turned off since I am using dyndns.org IP forwarding, however STUN is enabled at extension 310 end. Maybe this information may help.
     
  7. vinzer

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    Re: Very strange issue - please suggest WHY?

    no one has same problem ? :cry: anyone
     
  8. tpinnovations

    tpinnovations Member

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    Re: Very strange issue - please suggest WHY?

    Since your using the WRT series router you might looking upgrading the firmware to DDWRT, they have a special VoIP firmware that works quite well.
     
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  9. vinzer

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    Re: Very strange issue - please suggest WHY?

    Yes I have WRT router and already upgraded it to DD-WRT firmware. I am trying to find where is my problem. Why it drops call after 32 seconds even when all ports on remote extension forwarded to phone's IP ? I can not understand how all this works and how handshake happens between extensions. I tried to read in FAQ section but nothing related to such problem there. It is very annoying problem since it makes this software useless for our business :( But we like it very much, however can not properly use.
     
  10. tpinnovations

    tpinnovations Member

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    The problem is most likely not with the DDWRT router, But with the upstream modem. If your DSL is PPOE you may wish to bridge the modem and have the router handle the PPOE session. Most of the modems have some sort of firewall that can only be disabled by bridging or tinkering in the modem management console.

    You can contact your ISP for more information on how to do this.
     
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  11. vinzer

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    Thank you for this idea.
    Yes we have PPPoE DSL connection on the remote end.
    Modem is connected directly to the router and WRT router has Login and Password information for the DSL Internet Provider. It is setted up to control the modem's internet connection. In this case looks like our modem acts as a bridge and WRT controls this DSL modem.

    Today I tried to do the following:

    1. setup forwarding o the remote extension for port 5060 TCP and UDP to the phone's IP
    2. Shutdown UPnP on both ends (3CX server and remote extension)
    3. Set Keep Alive on 3CX Server end in settings
    4. made DMZ for the remote extension's IP

    Nothing helped :(

    Whenever we call from internal extension to external it stays connected with no problems, but as soon as Remote extension calls us the connection drops after 32 seconds with the message ACK not received.

    Please explain me: this message ACK is not received, what exactly it means. Who generate this message and based on what ?
    Am I correct: when remote extension calls internal, phone server waits until remote extension will send some sort of ACK packet to confirm connection. But remote extension for some reason does not send it or it sends it but it lost somewhere ? If my assumption is correct than the problem is not at the WRT (remote extension end) but somewhere at servers end because this ACK signal does not travel until server from remote extension. Please correct me if I am wrong. I want to get to the bottom of this since this is the only problem which is holds us from getting this software in the future for our office.
    Thank you very much for your help and sorry that I am so annoying on this problem. :p
     
  12. vinzer

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    In addition to previous message here is my verbose log of the call from extension 310 (external) to extension 303 (internal) which drops due to the missing ACK in 32 seconds. Am I correct that for some reason ACK has not been received by 3CX Server ? Just I want to get to the bottom of the problem here.

    ---------------------------------------------------------------------------------------------------
    23:06:19.765 [CM503008]: Call(2): Call is terminated

    23:06:19.765 [CM503008]: Call(2): Call is terminated

    23:06:19.578 [CM503008]: Call(2): Call is terminated
    23:06:19.015 [CM503020]: Call(2): ACK is not received

    23:05:47.187 [CM503007]: Call(2): Device joined: sip:303@192.168.0.113:5060

    23:05:46.984 [CM503007]: Call(2): Device joined: sip:310@174.91.207.28:5060

    23:05:46.984 [MS210005] C:2.1:Answer provided. Connection(proxy mode):74.59.81.48:9002(9003)

    23:05:46.984 [MS210001] C:2.2:Answer received. RTP connection: 192.168.0.113:16458(16459)

    23:05:46.984 Remote SDP is set for legC:2.2

    23:05:46.984 [CM505001]: Ext.303: Device info: Device Identified: [Man: Linksys;Mod: SPA Series;Rev: General] Capabilities:[reinvite, no-replaces, able-no-sdp, recvonly] UserAgent: [Linksys/PAP2T-5.1.6(LS)] Transport: [sip:192.168.0.51:5060]

    23:05:46.984 [CM503002]: Call(2): Alerting sip:303@192.168.0.113:5060

    23:05:39.281 [CM503024]: Call(2): Calling Ext:Ext.303@[Dev:sip:303@192.168.0.113:5060]

    23:05:39.281 [MS210004] C:2.2:Offer provided. Connection(proxy mode): 192.168.0.51:7002(7003)

    23:05:39.281 [CM503004]: Call(2): Route 1: Ext:Ext.303@[Dev:sip:303@192.168.0.113:5060]

    23:05:38.531 [CM503010]: Making route(s) to <sip:303@httcanada.dyndns.org>

    23:05:38.531 [MS210000] C:2.1:Offer received. RTP connection: 174.91.207.28:16426(16427)

    23:05:38.515 Remote SDP is set for legC:2.1

    23:05:38.515 [CM505001]: Ext.310: Device info: Device Identified: [Man: Linksys;Mod: SPA Series;Rev: General] Capabilities:[reinvite, no-replaces, able-no-sdp, recvonly] UserAgent: [Linksys/PAP2T-5.1.6(LS)] Transport: [sip:192.168.0.51:5060]

    23:05:38.140 [CM503001]: Call(2): Incoming call from Ext.310 to <sip:303@httcanada.dyndns.org>
    23:05:38.109 [CM500002]: Info on incoming INVITE:

    INVITE sip:303@httcanada.dyndns.org SIP/2.0

    Via: SIP/2.0/UDP 192.168.1.90:5060;branch=z9hG4bK-afbee8e0;received=174.91.207.28

    Max-Forwards: 70

    Contact: "Ekaterina Ivanova"<sip:310@174.91.207.28:5060>

    To: <sip:303@httcanada.dyndns.org>

    From: "Ekaterina Ivanova"<sip:310@httcanada.dyndns.org>;tag=1bdb91c6b92fabf8o0

    Call-ID: 482fc85e-b8db2640@192.168.1.90

    CSeq: 102 INVITE

    Expires: 240

    Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER

    Proxy-Authorization: Digest username="310",realm="3CXPhoneSystem",nonce="414d535c00d35c0102:ce5217cfbc13347ee8d30356415ccd3c",uri="sip:303@httcanada.dyndns.org",algorithm=MD5,response="fe99a642212003a3a091bc82c0631550"

    Supported: x-sipura, replaces

    User-Agent: Linksys/PAP2T-5.1.6(LS)

    Content-Length: 0
    -----------------------------------------------------------------------------------------------------
     
  13. tpinnovations

    tpinnovations Member

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    http://www.3cx.com/manual/3CXPhoneSystemManual31/phone-system17.html
    Turn to page 17.

    If your getting ACK error one of your ports isn't being forwarded to the 3CX box from the WAN side. Generally RTP packets

    On the 3CX side, turn off UPNP and perform a port forward of the ports in the above manual.

    Your setup should look like this

    Remote Side < ===== Interwebs ===== > 3CX Side

    UPNP On < ===== Interwebs ===== > UPNP Off
    No Port Forwards < ===== Interwebs ===== > Port Forward WAN to 3CX box
    STUN < ===== Interwebs ===== > STUN
     
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  14. Discovery Technology

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    Hi Vlad,

    This is a known issue and can occur in some instances with the older versions of the Linksys firmware (yes, even the DD-WRT version)

    You could try tomato which appears to work quite well and should be a little easier for you to drive.

    Here are a couple of links for you for the download:

    http://www.polarcloud.com/tomato

    http://www.icewalkers.com/Linux/Software/528740/Tomato-Firmware.html

    ...or simply Google "linksys tomato download" and you should get plenty of hits.

    Please note: There have been reports that by switching over to the Tomato version of the firmware you could experience streaming .avi videos over a Windows file share getting jumpy (or other types of real time traffic). If you see this, go into the Administration->Configuration section and selected “Erase all data in NVRAM memory”. This is recommended if you are switching from a different firmware version over to Tomato anyway, although be aware that this process will set everything back to defaults. After following these steps real time apps or streaming should be much improved.


    On another note, I would also suggest that you switch STUN back on - even if you are using a dynamic IP on your Internet Service.
     
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  15. vinzer

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    Thank you very much for your suggestions and help.
    It is important for me to understand where is the problem and which port is causing this problem. Whenever I call from internal extension to external it works well. Whenever external extension calls anywhere it hangs after 32 seconds. Which router or firewall causing it - 3cx server side or external extension side ? How to check it ?
    Here is the log from this morning after I completely shutdown uPnP and SPI on DLink router at the 3cx server side. I set forwarding for ports 5060 (both) 5090 (both) 9000-9009 (both) 3478 (both) from WAN to 3cx server IP and it still hangs after 32 seconds :( I just want to know which side causing this problem. Please suggest.
    Here is verbose log from this morning after remote extension called to 999 (voicemail) and has been disconnected after 32 sec.

    09:37:20.640 [CM503008]: Call(1): Call is terminated

    09:37:20.640 [CM503008]: Call(1): Call is terminated

    09:37:20.640 [CM503008]: Call(1): Call is terminated
    09:37:20.078 [CM503020]: Call(1): ACK is not received

    09:36:48.187 [CM503007]: Call(1): Device joined: sip:999@127.0.0.1:40600;rinstance=d12bee6f88dd02fd

    09:36:47.984 [CM503007]: Call(1): Device joined: sip:310@174.91.207.28:5060

    09:36:47.984 [MS210005] C:1.1:Answer provided. Connection(proxy mode):74.59.81.48:9000(9001)

    09:36:47.984 [MS210001] C:1.2:Answer received. RTP connection: 127.0.0.1:40610(40611)

    09:36:47.984 Remote SDP is set for legC:1.2

    09:36:47.984 [CM505001]: Ext.999: Device info: Device Identified: [Man: 3CX Ltd.;Mod: 3CX IVR;Rev: General] Capabilities:[reinvite, replaces, able-no-sdp, recvonly] UserAgent: [3CX IVR] Transport: [sip:127.0.0.1:5060]

    09:36:47.984 [CM503002]: Call(1): Alerting sip:999@127.0.0.1:40600;rinstance=d12bee6f88dd02fd

    09:36:46.890 [CM503024]: Call(1): Calling Ext:Ext.999@[Dev:sip:999@127.0.0.1:40600;rinstance=d12bee6f88dd02fd]

    09:36:46.703 [MS210004] C:1.2:Offer provided. Connection(proxy mode): 127.0.0.1:7000(7001)

    09:36:46.500 [CM503004]: Call(1): Route 1: Ext:Ext.999@[Dev:sip:999@127.0.0.1:40600;rinstance=d12bee6f88dd02fd]

    09:36:46.500 [CM503010]: Making route(s) to <sip:999@httcanada.dyndns.org>

    09:36:46.500 [MS210000] C:1.1:Offer received. RTP connection: 174.91.207.28:16464(16465)

    09:36:46.500 Remote SDP is set for legC:1.1

    09:36:46.500 [CM505001]: Ext.310: Device info: Device Identified: [Man: Linksys;Mod: SPA Series;Rev: General] Capabilities:[reinvite, no-replaces, able-no-sdp, recvonly] UserAgent: [Linksys/PAP2T-5.1.6(LS)] Transport: [sip:192.168.0.51:5060]

    09:36:46.093 [CM503001]: Call(1): Incoming call from Ext.310 to <sip:999@httcanada.dyndns.org>
    09:36:46.046 [CM500002]: Info on incoming INVITE:

    INVITE sip:999@httcanada.dyndns.org SIP/2.0

    Via: SIP/2.0/UDP 192.168.1.90:5060;branch=z9hG4bK-4bce58ae;received=174.91.207.28

    Max-Forwards: 70

    Contact: "Ekaterina Ivanova"<sip:310@174.91.207.28:5060>

    To: <sip:999@httcanada.dyndns.org>

    From: "Ekaterina Ivanova"<sip:310@httcanada.dyndns.org>;tag=4605507343107ba2o0

    Call-ID: 1e663987-bce4859e@192.168.1.90

    CSeq: 102 INVITE

    Expires: 240

    Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER

    Proxy-Authorization: Digest username="310",realm="3CXPhoneSystem",nonce="414d535c00d3efed63:97411d1d2c130d8e98e93a2401fd9810",uri="sip:999@httcanada.dyndns.org",algorithm=MD5,response="8d10c56732880a36009f1282c74fd1c5"

    Supported: x-sipura, replaces

    User-Agent: Linksys/PAP2T-5.1.6(LS)

    Content-Length: 0
     
  16. tpinnovations

    tpinnovations Member

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    I was under the impression that all of your routers where DDWRT based. The problem most likely lies in that dlink, replace it with a WRT54G and it should be ok.
     
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  17. vinzer

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    I was able to fix the issue. Now all calls from external extensions are ok after 32 sec. All what has been done was:

    In 3CX Server in Extension settings --> other --> disable "support Re-invite" for each external extension.

    I have no idea how to explain this but we tried it on two different external extensions when it is enabled and disabled and only when it is disabled there is no call drop in 32 seconds.

    On both ends we have firewalls. On both ends UPNP is Enabled. Only on 3CX end we have ports forwarded (5060, 9000-9049, 3478)
    On both ends STUN servers are enabled.

    Thank you very much to everyone who was trying to help me in resolving this issue 8)
    Vlad
     
  18. SY

    SY Well-Known Member
    3CX Support

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    Vlad,

    Could you please post (or send it to me) two wireshark captures for following cases:
    1. configure external extension as "supports re-invites=on" and then replicate the (problematic) call
    2. configure external extension as "supports re-invites=off" and then replicate the same (but successful) call

    This setting must not cause(or fix) this problem. It is a reason why I'm asking you for information

    Thanks
     
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  19. vinzer

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    Network topology as follows:

    3CX Server is on dedicated machine. Firewall on server machine is disabled. There is Router D-Link DIR635: UPnP is ON, SIP setting is OFF, Port Forwarding as follows:
    3478 both
    5060 both
    9000 - 9049 both

    STUN is enabled on 3CX server. Also dyndns.org service is in use for static IP.

    On the remote extension side:
    DSL internet.
    Router DD-WRT with v.23
    No single port is opened.
    UPnP is enabled on the router.

    Phone (adapter) is Linksys PAP2T
    STUN server is in use
    NAT enabled

    Please let me know if I may provide you with more information.

    Vlad
     
  20. SY

    SY Well-Known Member
    3CX Support

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    Vlad,

    Did you read my post?
     
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