What is the difference between "No address associated with name" and "Unknown host"

[Chuck Swiger]

On Dec 4, 2006, at 11:54 AM, a at zeos.net wrote:
> What is the difference between "No address associated with name"
> and "Unknown host":

The former means there is no A record in the DNS for the hostname,  
but there is a DNS record for the domain and that it answered the  
question as such.  The latter indicates that the domain itself was  
invalid, and you got an NXDOMAIN response rather than NOERROR.

> $ ping accounts.eirtrade.ie
> ping: cannot resolve accounts.eirtrade.ie: No address associated  
> with name
>
> and
>
> $ ping accounts.eirtrade.i
> ping: cannot resolve accounts.eirtrade.i: Unknown host

% dig accounts.eirtrade.ie

; <<>> DiG 9.3.2 <<>> accounts.eirtrade.ie
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 53319
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;accounts.eirtrade.ie.          IN      A

;; AUTHORITY SECTION:
eirtrade.ie.            10703   IN      SOA     auth01.ns.eircom.net.  
hostmaster.eircom.net. 2001031301 28800 7200 604800 86400

;; Query time: 1 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Mon Dec  4 15:09:19 2006
;; MSG SIZE  rcvd: 105

% dig accounts.eirtrade.i

; <<>> DiG 9.3.2 <<>> accounts.eirtrade.i
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 18893
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;accounts.eirtrade.i.           IN      A

;; AUTHORITY SECTION:
.                       10718   IN      SOA     A.ROOT-SERVERS.NET.  
NSTLD.VERISIGN-GRS.COM. 2006120400 1800 900 604800 86400

;; Query time: 1 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Mon Dec  4 15:10:35 2006
;; MSG SIZE  rcvd: 112

-- 
-Chuck