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looking up DNS aliases?

ocicat002
Level 1
Level 1

My DNS foo is limited.

I know that a Website has a number of domains which all resolve to the same server(s). Is there a way that I can determine what all domain names point to this single site? I've used dig before, but I don't know how to find all aliases.

Thanks for any insight shared.

3 Replies 3

Joe Clarke
Cisco Employee
Cisco Employee

You could do a full zone transfer, but many sites do not allow this for security reasons (in fact, they should NOT allow this except from trusted nodes). Try, for example:

host -t AXFR DOMAIN

You might get lucky.

Thanks for your reply, & thanks for mentioning the host utility. I'm getting a "Transfer failed" error in response, so I'm guessing today is not a lucky day. I'll dig some more (no pun intended...). Thanks, again.

Danilo Dy
VIP Alumni
VIP Alumni

Hi,

What you are trying to do is impossible.

You are trying to know all the FQDN pointing to the same web server or IP address.

If you know the domain, it is nearly possible if zone transfer is allowed by the DNS hosting the domain but this is mostly not permitted for security reason as already mentioned by Joe. You can try thoug as I still find some DNS that permits zone transfer to any :)

You can't be certain that only one domain have FQDNs pointing to 192.168.0.1. What if there are other domains FQDNs pointing to 192.168.0.1?

NOTE: Domain example is sample.com while FQDN is http://www.sample.com

Since multiple FQDNS are pointing to the same web server, this means that the web server is configured for virtual hosting. You have more luck in looking at the web server configuration. This is easy for Apache. However, this will only give you the entries in the web server virtual hosting configuration. DNS may still create an 'A' record map to the IP address of this web server but it will not work if its not added in the entries of t he web server virtual hosting configuration.

Regards,

Dandy