UNIX for Dummies Questions & Answers

We're moving an app from a server in our domain to a server hosted by the vendor in their domain.
This app had it's own domain setup that we're authoritative for.

Do I need to create a new zone file? zone-vendor_com and set up the CNAME records in this file? Or if I can just edit the one I have?

I've set this up before by creating a new zone file and adding the CNAME records but we were authoritative for all the domains involved. This time we're not authoritative for all the domains. So I'm not sure if I need another zone file or if I can edit the one I have already.

I did do a search in the forum first and I did find some threads about pointing CNAMES to external domains, and they did say to create a new zone file. But I didn't find one that made mention about the authoritative thing. Apologies for being so thick about it.

Below is the vendors note on what DNS changes need to made:
NOTE: Vendor also provides an xxx_com domain name for your business (domain_xxx_com) but we recommend you keep your existing hostname and alter your DNS entry to point to the new domain name. We strongly recommend you CNAME alias www_mydomain_org and mydomain_org to vendor_domain_xxx_com_ And *_www_mydomain_org and *_mydomain_org to *_vendor_domain_xxx_com rather than pointing your DNS to the new IP address.

Existing zone file I've edited. If I can use this file should I delete the lines that setup the A records?

Code:

; NAMED Configuration for www_mydomain_com Domain
 ;
$TTL 6h
$ORIGIN domain_com.
@    IN    SOA     dns_server_domain_org_ postmaster_domain_org_ (
                2014090902    ; serial
                3h          ; refresh
                1h          ; retry
                1w          ; expire
                1d )         ; minimum
;
;name servers
;
        IN    NS    dns_server_domain_org_
        IN    NS    ns1_secondarynameservers_net_
        IN    NS    ns2_secondarynameservers_net_
        IN    NS    ns3_secondarynameservers_net_
;
;comment out this line the day of the switch?
        IN    A    192_168_1_55 
;

        IN    MX 5    mailserver_mydomain_org_
;
;
;comment out this line the day of the switch?
www        IN    A    192_168_1_55 
        
;comment out this line the day of the switch?
*_www_domain_org_ IN    A    192_168_1_55 

;    Aliases
;uncomment these lines the day of the switch_ 

;mydomain_org       IN CNAME   vendor_domain_xxx_com_
;www_mydomain_org   IN CNAME   vendor_domain_xxx_com_
;*_mydomain_org     IN CNAME *_vendor_domain_xxx_com_
;*_www_mydomain_org IN CNAME *_vendor_domain_xxx_com_

---------- Post updated 09-11-14 at 04:24 PM ---------- Previous update was 09-10-14 at 06:36 PM ----------

skip it I've got it sorted out.

If you are not authoritative for a domain, you have no files for that domain, and normally no records for its hosts in any zone (unless you need to intercept some queries behind firewalls to point them to internal IPs, where a full.dotted.name. record is used). But you could be a slave server for it, if that makes sense in the reliability and latency models.

CNAMEs are just aliases, since in a well ordered world, the A lookup for a.b.c as 1.2.3.4 is the exact reverse of the PTR lookup, and any other names must be by CNAME. If you move the server, the CNAMEs must have the new IP and reside on the authoritative master. Ditto for the A and PTR records. This might be multiple servers, but there is only one authoritative master for each.