How to determine host aliases for particular machine

[Peter_17]

Hi All...

How can one determine the alias(es) for a machine without logging into it? Is there some method using nslookup?

HAGO,

Pete

[Christopher McCray_1]

If you do an nslookup on the server and if there is an alias associated with it, it will state so at the bottom of the output as Aliases: ailias_name.

Hope this helps
Chris

[Curtis Larson_1]

get into interactive nslookup

at the prompt type:

ls -a domainname > tmpFileName
exit

grep yourHost tmpFileName

this does assume your dns server has correctly assigned a CNAME for the aliases

[Edward Alfert_2]

Yes if it uses /etc/hosts instead of DNS.

take a look at the following 2 nslookups i did. The first lists aliases because it was able to find the computer in /etc/hosts. the second doesn't list aliases because it uses DNS which doesn't list aliases with an nslookup

# nslookup 192.0.0.2
Using /etc/hosts on: aistrend

looking up FILES
Name: aistrend
Address: 192.0.0.2
Aliases: aistrend.allinterior.com

# nslookup alfert.com
Using /etc/hosts on: aistrend

looking up FILES
Trying DNS
Non-authoritative answer:
Name: alfert.com
Address: 209.194.65.125

[Peter_17]

Sorry, but none of the suggestions work. If I have a fully qualified hostname, and perform a nslookup on it, it does not reveal an alias(es) associated with it. However, if I do a nslookup on a known alias, it returns the FQDN along with the alias. Also, If I perform a nslookup on the IP, it only returns the FQDN.

In interactive mode, the ls command comes back as not recognized.

Session examples as follows:

Here, entering the alias actually returns the ip, FQDN, & the alias:

[me@unixbox1]% nslookup
> thealias
Using /etc/hosts on: unixbox1

looking up FILES
Trying NIS
Trying DNS
Non-authoritative answer:
Name: realhostname.something.com
Address: 1.2.3.4
Aliases: thealias.something.com

>

Entering the FQDN does not return the alias:

> realhostname.something.com
Using /etc/hosts on: unixbox1

looking up FILES
Trying NIS
Trying DNS
Non-authoritative answer:
Name: realhostname.something.com
Address: 1.2.3.4

>

Entering the IP of the box does not return the alias:

> 1.2.3.4
Using /etc/hosts on: unixbox1

looking up FILES
Trying NIS
Trying DNS
Name: realhostname.something.com
Address: 1.2.3.4

>

Any and all insight apprecaited.

HAGO,

Pete

[Bernie Vande Griend]

non-authoritative answer implies that you are not pointed directly the the DNS server responsible for this domain. Can you identify its IP address. If so try this:
nslookup
> server IP_of_the_dnsmaster server
> ls -a domainname > filetocheck
> exit
You can then grep filetocheck for the host you want.

The ls option should work, perhaps its not because your /etc/resolv.conf is not pointed directly at the master DNS server.

[Peter_17]

Hmmm.. I have changed the nslookup server designator to the Primary, Secondary, and Tertiary DNS servers, all yeilding the same results. When I perform the ls -a command along with the domain, it always responds with
*** Can't list domain mydomain.com: Query refused

Pete

[Bill Thorsteinson]

DNS will only return aliases if the reverse mapping is
done for the aliases. Often only the official name is
reverse mapped. In this case you can not get
a list of all aliases.

hosts files often contain the fully qualified name
as well as the hostname, but you need to log into
a server with a hosts file. Other than the local
system only necessary entries will be found there.

The use of CNAME entries can create aliases for
servers that the administrator is unware of.