Response inline.
----- Original Message -----
From: "Dimitris Daskopoulos" <dimitris@xxxxxxxxxxx>
To: "GNU Gatekeeper Users" <openh323gk-users@xxxxxxxxxxxxxxxxxxxxx>
Sent: Saturday, November 04, 2006 5:13 AM
Subject: Re: ENUM Support for GNUGK
>
> Simon,
> thank you for your elaborate explanation of the possibilities!
> Indeed SRV support opens up a whole new are for routing solutions.
>
> I have a few questions on your example:
>
> Simon Horne wrote:
> >
> > Dimitris
> >
> > I initially contributed the ENUM routing policy to GnuGK and I use it
> > regularly with www.e164.org
> >
> > <http://www.e164.org/>ENUM is only ever designed to resolve the
> > signalling address. It cannot be used to resolve the RAS address for
> > placing LRQ's.
> > GnuGk does not use port 1720 by default so all ENUM records must point
> > to signalling port 1721.
> >
> > So this is the behaviour in GnuGk v2.2.4
> > [RoutingPolicy]
> > default=enum,dns
> >
> > ENUM
> > 1 900 123 4567 ---> user@xxxxxxxxxxxxx:1721
> >
> > DNS
> > gk.mysite.com: ---> 65.234.x.x:1721
> >
> > ACF tells EP to call 65.234.x.x:1721.
> >
> Perfectly understandable.
> >
> > Question:
> > =========================================
> > Is there a way to do both, i.e. first check if the user is locally
> > registered on an ENUM resolved gatekeeper
> > and allow the gatekeeper to forward it to the gateway, if the user is
> > not locally registered.
> > To do this we need to make GnuGk take the ENUM reply and
> > resolve it (LRQ) through a gatekeeper service, before attempting the call.
> > =========================================
> >
> > What you need to do is use the SRV policy prior to DNS. SRV policy is
> > currently available in the CVS version of GnuGk.
> > DNS SRV is covered by H.323 Annex O, these are special DNS addresses
> > which indicate the H.323 signal and RAS addresses of a particular domain.
> >
> > So
> > for gk.mysite.com the DNS records would look like this.
> > DNS 65.234.x.x
> > Signal Port (_h323cs_.udp) gk.mysite.com:1721
> > RAS Port (_h323ls_.udp) gk.mysite.com:1719
> >
> > Following the logic
> > ENUM
> > 1 900 123 4567 ---> user@xxxxxxxxxxxxx (note must use 1720 as signal
> > port of GK)
> >
> > SRV*
> > *preform SRV query on gk.mysite.com
> >
> > success:
> > Resolve _h323ls_.udp record to gk.mysite.com:1719,
>
> Does the SRV method always return the ras address?
> Is the signaling one returned in other cases?
It depends on whether a signalling address SRV record exists. If one does then it is used over the RAS address. There is a preference order.
>
> > preform LRQ for user
> > at gk.mysite.com:1719, LCF returns 210.93.x.x:1720 as the signalling
> > address of user.
> >
> ... if the user is locally registered, and if not, LCF may return the
> address of a gateway. Sounds like exactly what I asked for.
>
> > DNS
> > no SRV Record so resolve gk.mysite.com to 65.234.x.x
> >
> > ACF tells EP to call gateway directly at 210.93.x.x:1720
>
> You mean 210.93.y.y:1720 as gateway (as opposed to 210.93.x.x:1720 which
> was the endpoint signaling address further up).
No. Same function can be used for gateway or endpoint, I just have incorrectly used the word gateway instead of endpoint.
>
> > If no DNS SRV
> > record available then route to gatekeeper at 123.234.x.x:1720
> >
> I don't understand this last sentence.
> Unless it was meant to replace the previous one and not to complement
> it. Both statements assume "no DNS SRV record".
No the first one refers to endpoint registered locally at 210.93.x.x:1720 and the second, using DNS (no SRV) to resolve the gatekeeper address and route the signalling through the call signal address of the gatekeeper at 123.234.x.x:1720. Sorry for the confusion
>
> > So to fully answer you question
> >
> > [RoutingPolicy]
> > default=enum,srv,dns
> > (with the CVS version of GnuGk compiled with DNS support in pwlib)
> >
> Is there a reason for the DNS method to always follow the ENUM method?
> If the ENUM lookup always returns explicit addresses,
> e.g. 12345678@xxxxxxxxxx:1720
> do we need to append the DNS method?
> I tried to get this to work without dns, but with no success.
I think you might of highlighted an issue in the routing. In theory no it does not require DNS however as it is the form user@address it may need to use the DNS routing policy to resolve. This might need to be addressed.
>
> Semantically, the DNS method is a little different than all the other
> routing methods. Once other methods are matched, address resolution
> stops. But the DNS method is applied even after a previously successful
> routing step. So it has to follow any other method that may return
> non-explicit addresses for the call to proceed. Correct?
Yes.
Additional note: There is a major security risk in using ENUM and LRQ's (SRV records) to resolve an endpoint/gateway address, as the gatekeeper may need to receive a LRQ from a gatekeeper which is not predefined as a neighbor in the routing policy. I have redressed that by extending the neighbor policy to accept LRQ from non-neighbors (by default is switched off) and extending the authentication module to cover authentication of LRQ's. This function is still experimental.
Simon
>
> Thanks again for answering with such detail.
> Dimitris
>
> >
> > Simon
> >
> >
> >
> > At 07:35 PM 31/10/2006, you wrote:
> >
> >> Hi all,
> >>
> >> I have the following problem that I would like to discuss with others
> >> who use H.323 enum on GnuGk 2.2.4.
> >> The GnuGk 2.2.4 manual states:
> >>
> >> * |enum|
> >>
> >> The enum policy replaces the destination with the information
> >> returned by ENUM server, so you must have the appropriate routing
> >> policies to finally route the call after the enum policy. Usually
> >> you should also have the dns policy after the enum policy, since
> >> the new location is often returned in the form of
> >> 'number@gatekeeper' and the dns policy is needed to resolve this.
> >>
> >> Reading this, you expect that GnuGk will be able to resolve ENUM entries
> >> pointing to the responsible gatekeeper
> >> e.g. IN NAPTR 100 10 "u" "E2U+h323"
> >> "!^\\+(.*)$!h323:\\1@xxxxxxxxxxxxxxxx:1719!" .
> >>
> >> However, the above example will not work, because after the ENUM query
> >> is resolved and DNS policy is applied,
> >> GnuGk places a call to the Signalling Port of the ENUM resolved host.
> >> Thus, only an entry such as this may work,
> >> pointing to :
> >> e.g. IN NAPTR 100 10 "u" "E2U+h323"
> >> "!^\\+(.*)$!h323:\\1@xxxxxxxxxxxxxxxx:1721!" .
> >> assuming gnugk has a signalling port enabled (proxy or routed mode)
> >>
> >> 2006/10/31 12:25:19.261 5 Routing.h(168) ROUTING Checking
> >> policy ENUM for the request ARQ 7924
> >> 2006/10/31 12:25:19.291 4 Routing.cxx(1092) ENUM
> >> converted remote party xxxxx to xxxxx@xxxxxxxxxxxxxxxx:1719
> >> 2006/10/31 12:25:19.291 5 Routing.h(168) ROUTING Checking
> >> policy DNS for the request ARQ 7924
> >> 2006/10/31 12:25:19.291 5 Routing.h(174) ROUTING Policy
> >> DNS applied to the request ARQ 7924
> >> 2006/10/31 12:25:19.291 2 RasTbl.cxx(2293)
> >> CallTable::Insert(CALL) Call No. 160, total sessions : 1
> >> 2006/10/31 12:25:19.291 2 RasSrv.cxx(389)
> >> ACF|1.2.3.4:1720|8024_endp|14331|xxxxx:dialedDigits|yyy:h323_ID|false;
> >> 2006/10/31 12:25:19.291 3 RasSrv.cxx(232) RAS Send to
> >> 1.2.3.4:1719
> >>
> >> Where the routing policy is:
> >> [RoutingPolicy]
> >> Default=enum,dns
> >>
> >> In general, ENUM entries may point to specific IPs of endpoints
> >> listening on port 1720,
> >> or point to gateways for PSTN termination for a range of numbers.
> >>
> >> Is there a way to do both, i.e. first check if the user is locally
> >> registered on an ENUM resolved gatekeeper
> >> and allow the gatekeeper to forward it to the gateway, if the user is
> >> not locally registered.
> >> To do this we need to make GnuGk take the ENUM reply and
> >> resolve it (LRQ) through a gatekeeper service, before attempting the call.
> >>
> >> Is there a way to configure GnuGk to do this, or will it take extra
> >> development effort?
> >> We would be interested to hear how others are using H.323 ENUM, if at all.
> >>
> >> Regards,
> >> Dimitris Daskopoulos
> >> GRNET/RTS
> >>
> >> -------------------------------------------------------------------------
> >> Using Tomcat but need to do more? Need to support web services, security?
> >> Get stuff done quickly with pre-integrated technology to make your job
> >> easier
> >> Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
> >> http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
> >> <http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642>
> >> _______________________________________________________
> >>
> >> Posting: mailto:Openh323gk-users@xxxxxxxxxxxxxxxxxxxxx
> >> Archive: http://sourceforge.net/mailarchive/forum.php?forum_id=8549
> >> Unsubscribe: http://lists.sourceforge.net/lists/listinfo/openh323gk-users
> >> Homepage: http://www.gnugk.org/
> >
> > ------------------------------------------------------------------------
> >
> > -------------------------------------------------------------------------
> > Using Tomcat but need to do more? Need to support web services, security?
> > Get stuff done quickly with pre-integrated technology to make your job easier
> > Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
> > http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
> >
> >
> > ------------------------------------------------------------------------
> >
> > _______________________________________________________
> >
> > Posting: mailto:Openh323gk-users@xxxxxxxxxxxxxxxxxxxxx
> > Archive: http://sourceforge.net/mailarchive/forum.php?forum_id=8549
> > Unsubscribe: http://lists.sourceforge.net/lists/listinfo/openh323gk-users
> > Homepage: http://www.gnugk.org/
>
> -------------------------------------------------------------------------
> Using Tomcat but need to do more? Need to support web services, security?
> Get stuff done quickly with pre-integrated technology to make your job easier
> Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
> http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
> _______________________________________________________
>
> Posting: mailto:Openh323gk-users@xxxxxxxxxxxxxxxxxxxxx
> Archive: http://sourceforge.net/mailarchive/forum.php?forum_id=8549
> Unsubscribe: http://lists.sourceforge.net/lists/listinfo/openh323gk-users
> Homepage: http://www.gnugk.org/
------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
_______________________________________________________ Posting: mailto:Openh323gk-users@xxxxxxxxxxxxxxxxxxxxx Archive: http://sourceforge.net/mailarchive/forum.php?forum_id=8549 Unsubscribe: http://lists.sourceforge.net/lists/listinfo/openh323gk-users Homepage: http://www.gnugk.org/
