Hi See my doubt is if we can make an entry like this joe IN A 192.168.254. 3 (joe.example. com. www IN A 192.168.254. 3 (www.example. com.) so as u said here .. is top level example is below that and www is the host name It works with out issue.if i have 10 machine with different hostnames like fred,john etc etc. i can go on adding lines as fred IN A 192.168.254. 3 (fred.example. com. john IN A 192.168.254. 3 (john.example. com.) Even having so mnay entries wont harm.it works i treid. .. But at the same time i can use CNAME for the above entries. so my question is what is the logical reason or a satisfying technical reason behind using CNAME instead of having 10 different lines of 'A' record.
sameer --- On Fri, 24/4/09, b.sadhiq <[email protected]> wrote: From: b.sadhiq <[email protected]> Subject: [Linux_Mantra] Re: actual use of CNAME in DNS To: [email protected] Date: Friday, 24 April, 2009, 1:57 AM --- In Linux_Mantra@ yahoogroups. com, "sameer2803" <sameer2803@ ...> wrote: > > Hi all, > Please help me out > > i have hosted a site www.example. com so the DNS config in zone file will be > as: > ; zone file for example.com > $TTL 2d ; 172800 secs default TTL for zone > @ IN SOA ns1.example. com. hostmaster.example. com. ( > 2003080800 ; se = serial number > 12h ; ref = refresh > 15m ; ret = update retry > 3w ; ex = expiry > 3h ; min = minimum > ) > IN NS ns1.example. com. > joe IN A 192.168.254. 3 > www IN CNAME joe > Ignore if any mistake in the file. according to above file if we request for > www.example. com it will get the CNAME as joe and will follow the CNAME chain > unless it gets the A record for the site i.e 192.168.254. 3. > > > If am not wrong,We can write the above file as > > joe IN A 192.168.254. 3 > www IN A 192.168.254. 3 > So what is the actual reason for using CNAME.just saying its used for alias > wont do.when we can write as ablove why to use canonical name,we can straight > away give the IP with A record. > First of all, the following second entry is a host of example.com joe IN A 192.168.254. 3 (joe.example. com. www IN A 192.168.254. 3 (www.example. com.) u can write the following www.joe IN A 192.168.254. 3 (that means www.joe.example. com.) FQDN .. is your root server com is first level domain example is second level domain joe is third level domain www is a hostname For Cname joe IN A 192.168.254. 3 www.joe IN CNAME joe IN Future IF u change ur Address record, then no need of changing for www host. So if you have mutiple hosts pointing to the same A record then using cname is understandable. Regards. B.Sadhiq Cricket on your mind? Visit the ultimate cricket website. Enter http://beta.cricket.yahoo.com [Non-text portions of this message have been removed]
