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BYOC Premises - Use of NAPTR lookup and SRV records for DNS resolution on Edge devices

  • 1.  BYOC Premises - Use of NAPTR lookup and SRV records for DNS resolution on Edge devices

    Posted 30 days ago
    Hi All,

    For one customer, we have to configure a new external trunk with a new carrier.
    This new carrier provides us a FQDN to contact them.

    After trunk & Edge configuration, I have this error :


    After discussion with customer and carrier, we know now that this FQDN is not a simple DNS A Record.
    They are using NAPTR lookup and SRV records to resolve this FQDN.
    These Edges have been configured with Google public DNS.

    Can someone confirm that Genesys Cloud Edge supports NAPTR lookup and SRV records for DNS resolution ?

    Thank you.

    Regards,

    Karim Oudinot
    #SIP/VolP

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    Karim OUDINOT
    Orange SA
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  • 2.  RE: BYOC Premises - Use of NAPTR lookup and SRV records for DNS resolution on Edge devices

    Posted 24 days ago
    Hi,

    In addition, to be more precise, I read on help.mypurecloud.com that Genesys Cloud supports RFC 3263 (https://help.mypurecloud.com/articles/work-with-your-carrier-to-provision-a- sip-trunk /).
    Can you confirm that Genesys Cloud supports NAPTR records lookup and not only SRV resolutions ?
    I know for example that on Genesys Engage, SIP Server does not support NAPTR records lookup but only SRV resolutions.
    Is it also necessary to declare this FQDN without port in order to trigger the application of this RFC ?
    For information, this configuration has to be applied for SIP trunks provided by a major German carrier.

    Thank you.

    Regards,

    Karim Oudinot

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    Karim OUDINOT
    Orange SA
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  • 3.  RE: BYOC Premises - Use of NAPTR lookup and SRV records for DNS resolution on Edge devices

    GENESYS
    Posted 6 days ago
    Hi Karim,

    NAPTR is needed if the SIP User Agent transaction layer does not know which transportation protocol to use, more specifically which transportation protocol port to use to contact some other UAS.

    NAPTR should be used when telephone numbers are stored on DNS servers as NATPR records, i.e. the ENUMeration capability.
    Is this what the customers wants to achieve? I'm also wondering what this customer needs to use NAPTR resolution?

    We can't configure DID numbers as NATPR records in Genesys Cloud, we can configure routing correctly for known telephone numbers.

    Limitations we have:
    - It's not possible to set different IPs for signaling within same trunk.
    - Only DNS SRV method is supported.
    - Only numbers are allowed on the DNS SRV address.

    Our Edges support DNS SRV to lookup an external SIP Trunk.
    NAPTR is not needed because we already know the transport protocol and port.
    But, if the customer is asking edge HA must support active-active edges addressed via DNS SRV, that kind of HA can't be achieved
    HA should be achieved using a round-robin setup on the SBC from the carrier.

    What are the SIP devices you are implementing redundancy and high availability solution via DNS SRV for?
    Or does the scenario differ here; the customer has multiple edges and wants to be addressed by external SBC via DNS SRV?

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    Bert Barrez
    Genesys - Employees
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