Ping returns different results if asked ip address or hostname

Question

Alright, I've got an irritating problem. When I ping one of the servers in my company with

ping 192.168.1.62

I get my box ldmmit1 as the result. But when I use this line

ping ldmmit1

I get back ip address 192.168.1.184 with a name of 1st6cf1 as the return. Those are the correct hostnames for those boxes, but I can't understand why the dns server would route requests for ldmmit1 to 1st6cf1. I've done a traceroute, and the requests are handled by the same dns server.

I didn't set it up, so I don't know what or if the problem is located there, though the network guy couldn't see anything on his cursory check. At this point I'm not sure where the problem is, so any pointers would be appreciated.

is one of those IPs double-given to these two servers? Did you check if your DNS-server has old entrys for those names? — wullxz, May 25 '11 at 14:13

score 3 · Answer 1 · edited Jun 11 '20 at 10:02

This seems to be a name resolution issue. As such, ping and traceroute will not provide the most useful information. nslookup would more effectively help diagnose this issue.

What is the output of

nslookup ldmmit1

and

nslookup 1st6cf1

The DNS records may be incorrect.

Theoretically the name might be resolving via NetBIOS name service rather than DNS, but that depends on the version of Windows you're running, and requires a WINS server on the network, and that DNS resolution doesn't find anything.

There could also be relevant records in your /etc/hosts file. On my XP machine that's in C:\WINDOWS\system32\drivers\etc. But more than likely, it's just a DNS issue.

This TechNet article has lots of information regarding name resolution.

score 3 · Accepted Answer · edited May 25 '11 at 14:53

3

You'll want to check A records and reverse lookup records.

As mentioned, your server has an A record for ldmmit1 pointing to 192.168.1.184. Or, possibly a pointer record to 1st6cf1 . You've probably also got a reverse lookup record for 192.168.1.184 pointing to 1st6cf1.

You can use nslookup to help sort this out. Try these commands:
nslookup 1st6cf1
nslookup ldmmit1
Check for any alias entries in these two results. Also, check the reverse records for those IPs:

nslookup
>set type=PTR
>192.168.1.184
>192.168.1.62

See how the reverse addresses turn out. You may have things pointing in the wrong places.

edited May 25 '11 at 14:53

Steven Monday

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answered May 25 '11 at 14:35

Christopher Karel

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As it happens, we had both a set of bad PTR entries and a bad A record entry. Still figuring out how to change windows DNS A records. I'm a linux guy so the ui is unfamiliar to me. – Spencer Rathbun May 25 '11 at 14:44
@Spencer Rathbun - are you an administrator of the DNS server? – Bribles May 25 '11 at 15:14
Nope, but I talked with the guy who does have admin access and we got it resolved. – Spencer Rathbun May 25 '11 at 15:20

score 2 · Answer 3 · answered May 25 '11 at 14:19

2

Your DNS server likely has an A record entry for ldmmit1 with the IP of 192.168.1.184.

answered May 25 '11 at 14:19

HostBits

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This has happened to me. Easy fix when you know about it :) – Hondalex May 25 '11 at 14:35
Just blow away the incorrect A record in DNS and recreate a new one associating this host name/IP. – Chadddada May 25 '11 at 14:43

Ping returns different results if asked ip address or hostname

3 Answers3