Multiple A or CNAME?
Bill Moseley
moseley at hank.org
Sun Jun 4 15:51:09 UTC 2000
At 04:55 PM 06/03/00 -0600, Lee Howard wrote:
>>I'm mixed up about when to use CNAMEs when I have two names pointing to the
>>same IP number.
>From The Linux Network Administrator's Guide by Olaf Kirch:
[snipped]
>Because many systems will also use /etc/hosts for DNS resolution, I
>interpret the above to mean that you use an A record when there is an entry
>in /etc/hosts for it. If there is no entry for the system in /etc/hosts,
>then use CNAME. Okay, okay, I know this isn't black-and-white this way,
>but this is how *I* interpret it.
>
>There are admins out there who only ever use A records and never use CNAME,
>which works just fine. Outside of the NS, MX, and SOA pointing
>requirements, It's your preference, I'd guess.
Alright. So it's OK to use multiple A records to the same IP. And then, I
guess, on reverse, I can just pick which name I want to return in
in-addr.arpa requests.
I'm trying to make sure I get my setup correct before making it publicly
available. Most of it makes sense, but seeing how I'm just now learning
I'm sure I have mistakes. So, maybe it's just simpler to list my zone file
and see if anyone can point out errors.
I'm thinking about using Granitecanyon as my secondary -- or just run my
own. If I only run my own DNS will fail it my link is down, but if my link
is down I can't be reached anyway.
I'm only running one Internet-accessable machine at this point, but will
probably bring another online soon to split up the services.
I do have a few questions below. Any tips would be greatly appreciated!
@ 1D IN SOA mardy root (
2000060305 ; serial
1D ; refresh
1H ; retry
1W ; expiry
1D ) ; minimum
;; Name servers for hank.org
1D IN NS ns1
; 1D IN NS ns2 ; not online yet
1D IN NS ns1.granitecanyon.com.
1D IN NS ns2.granitecanyon.com.
;; Mail servers
; Can this point to, say, mail.hank.org. and
; have an A record for mail?
1D IN MX 5 mardy
;; IP number mapping
1D IN A 63.205.225.170
1D IN RP info.hank.org. info.hank.org.
info 1D IN TXT "Bill Moseley -- Hank.org"
;; Specific machines
gateway 1D IN A 63.205.225.169
mardy 1D IN A 63.205.225.170
ns1 1D IN A 63.205.225.170
dialup1 1D IN A 63.205.225.171
;ns2 1D IN A 63.205.225.174
; internal machines, use /etc/hosts instead
;selly 1D IN A 192.168.0.99
;cory 1D IN A 192.168.0.98
localhost 1D IN A 127.0.0.1
;; Aliases - for client computers to use
; I'm not sure why these shouldn't or should be
; A names instead.
smtp 1D IN CNAME mardy
pop3 1D IN CNAME mardy
ftp 1D IN CNAME mardy
www 1D IN CNAME mardy
Bill Moseley
mailto:moseley at hank.org
More information about the bind-users
mailing list