Where can I set DNS TTL of 3CX FQDN?

Discussion in '3CX Phone System - General' started by SECOIT GmbH, Jul 28, 2017.

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  1. SECOIT GmbH

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    Hi All,

    One of my customers wants to use 3CX PBX but at this point in time they don't have a fixed IP address.

    I'm using a 3CX FQDN in the format "[customer].3cx.de".
    The problem is that this A record for the 3CX FQDN has a TTL of 6 hours. For a dynamic IP address it should be rather 1 minute so 6 hours is by far too long for a dynamic IP address. 6 hours DNS TTL means a huge downtime for some functionality every time the IP address changes.
    Is there some place where I (or someone from 3CX) can set this?

    Thanks
    Michael
     
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  2. jed

    jed New Member

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    Hi Michael

    The Enterprise version should have only 2 min TTL.

    /Jesper
     
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  3. SECOIT GmbH

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    Hi Jesper,

    Thank you for your reply. Does that means Std/Pro can't use a dynamic IP address?
    6 hrs for dynamic IP is completely impractical dynamic IP addresses.

    Sounds like I'll have to use a Dynamic DNS service and use an own FQDN which would be unfortunate since it is quite comfortable to use a 3CX FQDN (don't have to worry about certificates for example).

    Is anybody reading this thread successfully using 3CX Std/Pro with a dynamic IP address?


    Thanks,
    Michael
     
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  4. jed

    jed New Member

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    Hi Michael

    I think the 6 Hour TTL is a political decision, to give some benefit to use the Enterprise version.

    That said, we have a costumer running PRO and Dynamic IP and the "failover" happens within 20 Min. on this installation using 3CX FQDN.

    /Jesper
     
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  5. SECOIT GmbH

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    Hi Jesper,

    20 Minutes? That means your customer is either extremely lucky or their DNS server is ignoring the TTL and keeps querying the authorative DNS server even the TTL has not expired yet. :)
    I can easily manipulate my customer's DNS server but for any remote workers or when people are travelling (using hotel internet for example) that's out of my influence.

    Well, guess I will need to use a Dynamic DNS service then and issue a own certificate. :(
     
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