DNS and NAME BASED APACHE

[Chip Old]

On Sun, 15 Jul 2001, Christopher Meiklejohn wrote:

> If there were going to be a large number of zones.. it might
> be more efficient to use the $INCLUDE directive, because
> if the IP is to ever change, changing 50 zone files woulnd't
> be the best use of your time.
>
> With the $INCLUDE you could include one file with the www A records
> for every domain.
> [snip]

In most web hosting scenarios the zone file is going to be exactly the
same for every hosted domain.  In that case rather than create a separate
zone file (or include file) for each zone, it's more efficient to simply
use a single generic zone file for all the hosted domains.  Here's an
example, assuming the hosting domain is "hostdomain.com", the generix zone
file is "db.virthosts", and you're doing name-based virtual hosting in
Apache:

;
; /var/named/db.virthosts
;
$TTL 6h  ; Default TTL 6 hours
@  IN  SOA  ns1.hostdomain.com.  admin.hostdomain.com. (
                                2001071500      ; Serial Number
                                6h      ; Refresh after 6 hours
                                1h      ; Retry after 1 hour
                                20d     ; Expire after 20 days
                                1h )    ; Negative caching TTL 1 hour
;
; Name Servers
;
                IN      NS      ns1.hostdomain.com.
                IN      NS      ns2.hostdomain.com.
;
; Mail Exchangers
;
                IN      MX      10      smtp1.hostdomain.com.
                IN      MX      100     smtp2.hostdomain.com.

;
; Hosts
;
www             IN      CNAME   virthosts.hostdomain.com.

Of course the zone files for hostdomain.com and <whatever>.in-addr.arpa
must already contain A and PTR records for ns1, ns2, smtp1, smtp2 and
virthosts.

Then in your named.conf, the "file" directive for each hosted zone points
to that single generic file, like this:

zone "abc.com" {
        type master;
        file "db.virthosts";
};

zone "xyz.org" {
        type master;
        file "db.virthosts";
};

In most web hosting scenarios that's all you need.  A hosted domain needs
its own zone file only if that domain needs something not present in the
generic zone file.

-- 
Chip Old (Francis E. Old)             E-Mail:  fold at bcpl.net
Manager, BCPL Network Services        Phone:   410-887-6180
Manager, BCPL.NET Internet Services   FAX:     410-887-2091
320 York Road
Towson, MD 21204  USA