Using SRV records in DNS

Improving the Internet is an important task. I see much improvement by using SRV records in DNS.
what are SRV records?
Basically just another type of RRs that can be used for your domain. You simply need to add them to your existing DNS zone files to make this work.
Besides being hip and cool you get a great deal of new features!

what do SRV records look like?
basically they describe a service and return a port (service) and a name to the client. But let us have a look at an example:
db.example.com:
  _http._tcp	SRV	0 0 80	webserver.example.com.
  (...)
  webserver	IN	A	1.2.3.4

This very simple example does nothing else than -- provided that your browser is aware of SRV records -- convert your query for http://example.com to _http._tcp.example.com and then ask your DNS server for this name.
The answer it gets (if you want to know what the two zeros do, read rfc2782!) basically tells him to look at webserver.example.com (which resolves to 1.2.3.4 via normal A record) using port 80.
Considering this simple example you might notice that you can use DNS for service redirection in any way you like. You may even specify several SRV records for one service and provide load balancing information... all in all you can only win ;-)

where can I get further information?
First this is a standard described in rfc2782. You might also find http://dns.vanrein.org/srv/ quite useful.

what can I do to support this idea?
(1) add SRV records to your DNS.
(2) ping your software vendor to support this!
It is a pitty that this simple protocol extension is not widely implemented yet.
I voted for using SRV records in KDE/Konqueror! It seems that this is already integrated into KDE 3.5 -- great work!
There is a great FTP command line client available that uses these records: LFTP. It is available for Debian users via apt. (There is just one thing: to use those SRV records add a line 'set dns:SRV-query y' to /etc/lftp.conf)

enjoy!



This page is maintained by Adi Kriegisch.