* * * * *
A clarification on an interesting point
A friend of mine wrote in, having read what I wrote about DNS (Domain Name
Service) [1] and asked for some clarifications. And yes, rereading what I
wrote, I should probably pass on what I wrote back.
>
>
> > If someone typed this into their web browser:
> >
> >
http://www.example.com
> >
> > … would they be redirected to:
> >
> >
http://www1.example.com:8080
> >
> > ????
> >
> > I've never seen this work so I'm curious if that's how this is resolved
> > by the nameserver.
> >
>
> It doesn't quite work that way. Normally, given a URL (Uniform Resource
> Locator)
>
>
http://www.example.com/
>
> a browser would extract out the host portion, and do a DNS A record lookup:
>
>
> ip = dns_resolve(host,A_RR);
>
> and if a port wasn't specified, use port 80 as a default:
>
> connection = net_connection(ip,TCP,80);
>
> Using the SRV record (which, to my knowledge, isn't used by any web browser
> that I know of currently), the code would look something like (for now,
> ignoring the priority codes and multiple servers issues):
>
>
> srvinfo = dns_resolve("_http._tcp" + host,SRV_RR);
> ip = dns_resolve(srvinfo.host,A_RR);
> connection = net_connection(ip,TCP,servinfo.port);
>
> >
> It's handled completely at the DNS level and no HTTP (HyperText Transport
> Protocol) redirect is sent at all. Unfortuately, nothing much (except for
> some Microsoft products, and Kerberos installations oddly enough) use the
> SRV records, which means …
>
> > PS: I have 2 never-used-domains (XXXXXXXXXXXX and XXXXXXXXXXXXXXXX) that
> > I'd like to point to my home unix box. Unfortunately, XXXXXXXX blocks all
> > port 80 traffic … I'm on the hunt for a free dynamic DNS provider that
> > will handle port forwarding or give me the ability to edit the DNS
> > records manually … with the end result being that I want all traffic for
> > these two domains to reach my home machine.
> >
>
> You can't use them for this. Sorry.
>
> You can add the records if you want (I have) but don't expect anything to
> use them anytime soon.
>
[1]
gopher://gopher.conman.org/0Phlog:2002/04/20.3
Email author at
[email protected]
