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There are some anomalies on a Virtuozzo virtualized Debian 4 (I know, I'm gonna upgrade this one asap, but there dependences). We run some Websites on this one. And a view Days ago exmi4 wasnt able to send mails to SOME people. I'll use live.com as exampledomain!

So some of this people got mails and some didn't.
Some of the mails got stuck in the queue, and after 2 days they went out!!
My Nagios never showed problems with the internet connection or disk space

Now i wanted to install "dig" to look how he's solving the dns request. And this Debian tells me he doesn't know dig..

Long story made short, Debian is able to download sites with exact IP or even with wget live.com, but it is not able to ping live.com.

I'm 99% sure that the networking is right and the routing too!

Some examples of my tring below:

wget live.com

downloads the site

ping live.com
ping http://www.live.com
ping http://live.com


ping: unknown host live.com


i now use heise.de not live.com any more.
and i found out i can ping the heise.de server by using it's IP-address.

myserver:~# ping
PING ( 56(84) bytes of data.
64 bytes from icmp_seq=1 ttl=248 time=12.7 ms
64 bytes from icmp_seq=2 ttl=248 time=12.6 ms
64 bytes from icmp_seq=3 ttl=248 time=12.9 ms
64 bytes from icmp_seq=4 ttl=248 time=13.1 ms
64 bytes from icmp_seq=5 ttl=248 time=13.1 ms

--- ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4001ms
rtt min/avg/max/mdev = 12.671/12.924/13.163/0.238 ms


myserver:/etc/apt# dig heise.de

; <<>> DiG 9.3.4-P1.2 <<>> heise.de
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 40551
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 5, ADDITIONAL: 3

;heise.de.                      IN      A

heise.de.               2266    IN      A

heise.de.               1622    IN      NS      ns.pop-hannover.de.
heise.de.               1622    IN      NS      ns.s.plusline.de.
heise.de.               1622    IN      NS      ns.plusline.de.
heise.de.               1622    IN      NS      ns2.pop-hannover.net.
heise.de.               1622    IN      NS      ns.heise.de.

ns.plusline.de.         265     IN      A
ns.pop-hannover.de.     5113    IN      A
ns2.pop-hannover.net.   15150   IN      A

;; Query time: 2 msec
;; WHEN: Tue Oct  9 13:03:50 2012
;; MSG SIZE  rcvd: 216
share|improve this question
Do you use a proxy server? –  boburob Oct 9 '12 at 10:17
what do you have in /etc/resolv.conf? –  Mike Pennington Oct 9 '12 at 10:20
I don't use a proxy, and in my resolv.conf i have my 2 nameservers, i've tried to delete one out and let just one work. But same story. –  zwarag Oct 9 '12 at 10:22
that doesn't answer the question. We need to see the contents of /etc/resolv.conf –  Mike Pennington Oct 9 '12 at 10:24
nameserver nameserver –  zwarag Oct 9 '12 at 10:26
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1 Answer

up vote 2 down vote accepted

ping: unknown host live.com

An unknown host error refers to problems with name to ip address resolution. AFAICT, you're not having that problem as long as you use and in /etc/resolv.conf...

[mpenning@tsunami tests]$ dig +short @ live.com
[mpenning@tsunami tests]$ dig +short @ live.com
[mpenning@tsunami tests]$

That said, what you're seeing could be related to trying to use ping http://live.com. Do not use the http:// prefix on your pings... that is only meaningful to a web browser.

FYI, live.com does not return pings, so you should not expect any to be returned... they should all time-out...

[mpenning@tsunami tests]$ ping -w 1 live.com
PING live.com ( 56(84) bytes of data.

--- live.com ping statistics ---
1 packets transmitted, 0 received, 100% packet loss, time 0ms

[mpenning@tsunami tests]$


I get this when I ping heise.de...

[mpenning@tsunami tests]$ ping heise.de
PING heise.de ( 56(84) bytes of data.
64 bytes from redirector.heise.de ( icmp_req=1 ttl=241 time=144 ms
64 bytes from redirector.heise.de ( icmp_req=2 ttl=241 time=144 ms
64 bytes from redirector.heise.de ( icmp_req=3 ttl=241 time=144 ms
64 bytes from redirector.heise.de ( icmp_req=4 ttl=241 time=143 ms
--- heise.de ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3002ms
rtt min/avg/max/mdev = 143.734/144.344/144.730/0.598 ms
[mpenning@tsunami tests]$
share|improve this answer
this helps my understanding!; but i used to try it without http:// and i used heise.de too, to try the ping. It actually does not matter with domain i use. I thing i have to install dig from source and figure it out that way.. –  zwarag Oct 9 '12 at 10:34
please see my edit about heise.de... unless a firewall is blocking the pings, you should see them returned from heise.de –  Mike Pennington Oct 9 '12 at 10:40
yes i use know the ip of heise.de directy! and it works, but this is not the solution. somthing's messign up the resolving process... –  zwarag Oct 9 '12 at 10:44
please post the results of dig @ heise.de and dig @ heise.de –  Mike Pennington Oct 9 '12 at 10:53
I can't install dig. BUT i can do: host heise.de and it returnes: heise.de A –  zwarag Oct 9 '12 at 11:02
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