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Having problems with firewall

Discussion in '3CX Phone System - General' started by mevans91, May 29, 2017.

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  1. mevans91

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    Hi everyone,

    I'm having problems with my firewall configuration. I have forwarded ports 9000-9500 to the 3cx server (at 192.168.1.22).

    When I run the firewall checker, about 10% of the ports randomly fail the firewall test.
    For example, on test 1 ports 9019-9022 (and a bunch of others) will fail but then on test 2 they'll be fine but 9022-9043 will fail instead.

    Any ideas as to what is going on, or what I should check?

    Thanks,
    Matt
     
  2. pact

    pact New Member

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    Hi Matt,

    What router/firewall are you running?
     
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  3. Hello @mevans91

    It would be very helpful if you show us what you have configure as port forward to your firewall. If it is possible add a screenshot.
     
  4. mevans91

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  5. mevans91

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    Hm. Okay.
    I'll see if I can get wireshark to work, I haven't used it in linux before.

    Matt
     
  6. StefanW

    StefanW Head of Customer Support and Training
    Staff Member 3CX Support

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  7. craigreilly

    craigreilly Well-Known Member

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    I had this issue with my Miktrotik until a fairly recent firmware update. Port failure was random but system always seemed to work fine and stable.
     
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  8. OCWI

    OCWI New Member

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    Any SIP ALG involved anywhere? Disable that, it may also be worth a call to your ISP to ensure your modem is in "STRAIGHT bridge" mode. For some reason ISP's lately have internally defined a difference between bridge mode and straight bridge mode.
     
  9. DSXDATA

    DSXDATA New Member

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    ALG will consistently break, not a likely cause of random behavior. Might be an aggressive intrusion detection feature on the router. That router has an integrated VOIP client which can most certainly wreak havoc. If you can put it in bridge mode and use your own "known-good" router, you will probably be happier.
     
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  10. OCWI

    OCWI New Member

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    In our experience the ISP's ALG is almost always the cause of random behavior. In our are we have Charter/Spectrum.
     
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