DNS

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: Domain Name Service

... IIRC

... not to be confused with DNA.

(One looks up a short code from a readable reference, the other looks up a large object from a long code)

The nice webby thing thats points your browser in the right direction.

Most of what MoonShadow knows about it usually comes from whichever version of [this] Google last [threw] at him.

Does anyone know how a CNAME record works? I'm trying to set up an address so that xyz.com automatically forwards to xyz.co.uk and I believe the CNAME record is the one I am supposed to use but I can't get it working. At the moment it looks like I'm going to have to set up a whole web site, just to contain a redirect page, which can't be right... --Kazuhiko

A CNAME record specifies an alias for a domain name. So xyz.com TTL IN CNAME xyz.co.uk sounds like what you want. CNAME records must always point to A records, though - so you need to make sure that the entry for xyz.co.uk isn't another CNAME. What exactly is the problem you're having? - MoonShadow

: I have no real way of telling if xyz.co.uk is a CNAME or not, so that might be the problem I guess. Other than that that sounds like what I did. The domain name ended up referring to the default local website for some bizarre reason. Not that important I guess, since I've now set up the forwarding site, but still annoying. --Kazuhiko

: You would have needed to tell Apache? on xyz.co.uk to handle URLs beginning with xyz.com the same way as xyz.co.uk. --B

Say I have a domain foo.com with entries a.foo.com, b.foo.com etc. How can I include an entry for foo.com itself? --Lmm

: When you register the domain the registrar will either provide name servers for you to use, or you will have to enter the addresses of two name servers that you control. These can have names in the same domain as the domain you register, but if so there is some magic done (which the registrar does). Then you just add A records (for hostname to IP address resolution) and CNAME records (for 'this host is the same as this host' entries). If you had foo.com you could add an A record for a.foo.com, and likewise for foo.com itself. Why do you ask? Do you have a specific problem? --RobHu

: I meant the zone file as below, sorry for confusion, and thanks to everyone. --Lmm

: If you mean, "what's the syntax to use in the zone file", just omit the subdomain name entirely, e.g.:

 $ORIGIN foo.com
 $TTL 12345
 @    IN     SOA   .... ( ... )
 .
 .
 .
      IN     A      12.34.56.78
 a    IN     A      23.45.67.89
 b    IN     A      34.56.78.90
 .
 .
 .

: Alternatively, you can give an FQDN:

 $ORIGIN foo.com
 $TTL 12345
 @    IN     SOA   .... ( ... )
 .
 .
 .
 foo.com.     IN     A      12.34.56.78
 a    IN     A      23.45.67.89
 b    IN     A      34.56.78.90
 .
 .
 .

(that trailing dot is important!). HTH --MoonShadow

Of course, all this assumes you're using BIND --RobHu

If you have a choice I would recommend djbdns. It simple, secure, and uses few resources. --RobHu

Personally, I would recommend something that follows [accepted standards]. But your call. - MoonShadow

Which parts of the RFC is djdbns not compliant with? --RobHu

: Well, section 5, on the format of master files, that I referred to when producing the above examples is particularly relevant to the discussion. - MoonShadow

Agreed - and while the file format is much nicer than BIND's, DJB's licenses also mean that djbdns doesn't fit into a sensible security upgrade regime. -- SGB

Oh, don't even start on that. Many [rants] have been written. - MoonShadow

Has there ever been a vulnerability for djbdns? I'm not sure there has. --RobHu

: Arguably, yes. The dnscache component can be made to [eat up server resources] if other people's delegation records are set up in a certain way. However, there are no vulnerabilities that DJB will admit to, so none that will get fixed. --SGB

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