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VOIP cannot use Firewall?

  • This topic has 3 replies, 1 voice, and was last updated 18 years ago by Chaithanya.
Viewing 4 posts - 1 through 4 (of 4 total)
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  • #22005 Reply
    Jacky Wong

    Dear Sir,

    I tried install the Linux Firewall to protect our VOIP system but I found
    that the voice delay increased after it.
    Is it impossible to install any firewall to protect VOIP system? If no,
    What kind of firewall I can use. Or Any suggestion can let me setup that
    only allow specified IP address to access our internal VOIP network. Please
    Many Thanks.

    #22006 Reply

    I know that the cisco PIX FW can open up dynamic holes in the firewall for 323 and SIP.

    #22007 Reply


    Can you send some more info on the linux set up that you were using please.

    just e-mail me at


    #22008 Reply


    I think firewalls shoudn’t be a problem for VoIP. There could be several other reasons for the delay which you saw when you introduced a firewall. I saw watchguard as well as pix firewall working very well and allowing voice traffic. You should allow port 1720 for voip communication. Please try this option…..

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Reply To: VOIP cannot use Firewall?
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