I believe I asked already the question but I cannot find an answer.
Is such a project (standardizing SRV support for HTTP) ontopic for
this WG?
Forwarded message 1
The basic problem is that there is no documentation on how
to it and it is a protocol violation to do this to old
(includes http) protocols without writing a transition
(retrofiting) specification.
I attempted to write such a document years ago but got zero
traction from browser and proxy developers. I attempted to
revive it and still got zero traction from browser and proxy
developers.
http://www.watersprings.org/pub/id/draft-andrews-http-srv-01.txt
Mark
> Your basic problem here is that it's up to the web browser to do the
> right thing, and nearly all of them don't. I believe there might be
> one or two (Opera?) that do, but the major browsers (IE, Firefox, and
> Safari) do not.
>
> As a side note, if browsers did support SRV records, you would want
> another RRSet named _http._tcp.www, to cover the case when users enter
> "www.cska.dom" into their browsers.
>
> Since a purely DNS-based solution won't work, you might consider
> something at the HTTP level, or you might want to consider finding a
> way to force your DNS records to react to an outage. For example:
>
> - I believe F5 makes some appliances...
>
> - You could have a process watching your web servers and using dynamic
> update to change the A record when needed. I believe there are canned
> solutions for this as well.
>
> - You could put a hidden master name server on each web server, and
> configure your publicized DNS servers as slaves, with the backup
> master listed second. Add "multimaster true;" to each slave zone
> statement, if I recall the syntax correctly. Then if web server A goes
> down (the whole machine, or its connection to the Internet), the DNS
> servers would switch over to server B and its different data. Use a
> short refresh interval to make this more responsive. Note that if the
> web server process fails, but the server machine is still up, you're
> out of luck here.
>
> In general, this is a tough issue to solve. It would be very nice if
> the browsers supported SRV records, because then we could stop playing
> all these games, but unfortunately they do not.
>
> Chris Buxton
> Professional Services
> Men & Mice
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> Email: cbuxton@menandmice.com
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>
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> On Jan 10, 2008, at 11:35 AM, Radi Tzvetkov wrote:
>
> > Trying to set a simple fail over when site A is active and site B is
> > standby. When A fails all traffic goes to B. Should be pretty easy
> > with SRV records but my experimental BIND server does not deliver the
> > expected result. Also i am not sure if these records are implemented
> > in IE7 or Firefox.
> > Aslo any suggestions on how to support multiple grographically
> > dispersed web
> > servers are welcome.
> >
> > Here is the zone file:
> >
> > $TTL 86400
> >
> > @ IN SOA ns1.cska.dom. dnsadmin.cska.dom. (
> > 5 ; serial number YYMMDDNN
> > 28800 ; Refresh
> > 7200 ; Retry
> > 864000 ; Expire
> > 86400 ; Min TTL
> > )
> >
> > NS ns1.cska.dom .
> > NS ns2.cska.dom.
> >
> > MX 10 mail.cska.dom.
> >
> >
> >
> > _http._tcp.cska.dom. SRV 10 1 80 host1.cska.dom.
> > _http._tcp.cska.dom. SRV 20 0 80 host2.cska.dom.
> >
> > cska.dom. A 10.1.1.13
> > host1.cska.dom. A 64.233.167.99
> > host2.cska.dom. A 10.1.9.1
> >
> >
> > ns1.cska.dom. A 10.1.9.1
> > ns2.cska.dom. A 10.1.9.1
> > mail.cska.dom. A 10.1.9.1
> >
> > ; NO other services are supported
> > *._tcp SRV 0 0 0 .
> > *._udp SRV 0 0 0 .
> >
> >
> > $ORIGIN cska.dom.
> >
> >
> >
>
>
--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: Mark_Andrews@isc.org