Date: Fri, 23 Oct 2009 15:56:40 +0100 From: krad <kraduk@googlemail.com> To: Sean Cavanaugh <millenia2000@hotmail.com> Cc: "freebsd-questions@freebsd.org" <freebsd-questions@freebsd.org> Subject: Re: FW: DNS Question Message-ID: <d36406630910230756x13480e1n3194f13ddbe47cd6@mail.gmail.com> In-Reply-To: <BAY126-W8642EA12C68270F81DA77CABD0@phx.gbl> References: <4AE1A1D0.8060402@pixelhammer.com> <BAY126-W8642EA12C68270F81DA77CABD0@phx.gbl>
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2009/10/23 Sean Cavanaugh <millenia2000@hotmail.com> > > > > > Date: Fri, 23 Oct 2009 08:30:08 -0400 > > From: dave.list@pixelhammer.com > > To: freebsd-questions@freebsd.org > > Subject: DNS Question > > > > Good morning. > > > > I have been asked by my co-workers and sales why I always create a A > > record for new domains we host instead of a CNAME. > > > > The issue I run into lately with some domains is that a client has a > > website with a industry host such as frank.relator.com and he wants to > > have DNS point www.frank.com to frank.relator.com with a CNAME. The > > client does not want an A record for frank.com. > > > > Somewhere, in a class far far away, I was taught a DNS zone had to have > > a A record to function properly. I can't seem to locate anything in the > > RFCs. > > > > Am I wrong? > > > > > I think you are confusing basics of DNS records. you are partially correct > in that a DNS zone needs an initial A record to be able to translate a name > to an IP, but there is nothing wrong about setting up a CNAME to point to a > record in a different zone instead. you just cannot do a zone that has a > CNAME only that does not at some point to a valid A record. CNAMEs are > forwarders only whereas A records are actual lookups. > > for proper way to set this up.... > > The A record would be assigned for the main name that you want to associate > to an IP address. > The CNAME record just relates a different name to that original name. this > allows you to change the IP address of the server and only have to update > the original A record instead of every DNS record for that server. > > for small number of vhosts, this would not really be an issue, but imagine > if you were hosting a couple hundred vhosts from a single IP and then had to > change that IP because you switched your ISP. It would take you a LONG time > to update them if they were all A records, but only a couple of seconds if > you had it properly set up as CNAME's > > www.bobshosting.com A 192.168.0.1 > www.vhost1.com CNAME www.bobshosting.com. > www.vhost2.com CNAME www.bobshosting.com. > www.vhost3.com CNAME www.bobshosting.com. > www.vhost4.com CNAME www.bobshosting.com. > > > > -Sean > > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to " > freebsd-questions-unsubscribe@freebsd.org" > I try to use CNAMES as much as possible, for one very good reason. If say I have web server with 1000 vhost on it. I have one A record for the server and all the cnames point at that A record. Now i need to change the ip of the server. I update the A record and add a reverse record and im done. IF I had done it your way with all A records I would now have to go and edit another 1000 records. Even worse if some of these domains are not under my control I have to go and liaise with customers, or other third parties, and it becomes a complete mess. The chances of me convincing them all and coordinated it correctly are minimal 8(
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