Amazon ELB CNAME record not working

Question

Hi there,

I have set up my EC2 infrastructure behind an ELB instance and by using the ELBs DNS name everything works as expected. Now i wanted to forward a subdomain of my main project domain to the ELBs DNS Name with a CNAME entry. I did this about 12 hours ago and it doesnt seem to work, and i dont know why. The subdomain just cant be resolved.

This is the DNS entry which was processed from my DNS provider without errors yesterday:

@ IN A 111.111.111.111
localhost IN A 127.0.0.1
mail IN A 111.111.111.111
www IN A 111.111.111.111
ftp IN CNAME www
beta IN CNAME myelbnamehere.eu-west-1.elb.amazonaws.com
imap IN CNAME www
loopback IN CNAME localhost
pop IN CNAME www
relay IN CNAME www
smtp IN CNAME www
@ IN MX 10 mail

Using nslookup, all the subdomains and main domain gets looked up correctly, but beta.domain.com doesnt. I get "** server can't find beta.domain.com: NXDOMAIN"

What am i doing wrong ? Do i need to wait longer ? When i use the ELB DNS name directly everything works as expected.

When i do an NSlookup on my providers DNS Server, the CNAME gets resolved, but it looks like any other DNS server cant find the subdomain

thanks in advance

Answer 1

If that's an exact quote from your DNS GUI, then you appear to be missing the trailing . from the entry for beta. It should read:

beta IN CNAME myelbnamehere.eu-west-1.elb.amazonaws.com.

Without the ., it'll get parsed as:

beta IN CNAME myelbnamehere.eu-west-1.elb.amazonaws.com.domain.com.

which of course doesn't exist.