Ping: Unknown Host Not Found on Ubuntu 11
 

Hello,

I am unable to ping hosts via their DNS names using Linux Ubuntu 11.

Resolve.conf has our Cisco RV220W router's IP Address as Primary DNS and this router also handles all DHCP requests. Hosts.allow file has Allow ALL local@"our workgroup name" set as well.


Resolve.conf File Output:
k@cydsk3:~$ cat /etc/resolv.conf
# Generated by NetworkManager
domain cnmc
search cnmc
nameserver 192.168.0.220
nameserver 208.67.222.123


End of File


Note: We also utilize various Windows XP,7 workstations that seem to resolve hostnames normally.

Hosts.allow file Output:

# /etc/hosts.allow: list of hosts that are allowed to access the system.
# See the manual pages hosts_access(5) and hosts_options(5).
#
# Example: ALL: LOCAL @some_netgroup
# ALL: .foobar.edu EXCEPT terminalserver.foobar.edu
#
# If you're going to protect the portmapper use the name "portmap" for the
# daemon name. Remember that you can only use the keyword "ALL" and IP
# addresses (NOT host or domain names) for the portmapper, as well as for
# rpc.mountd (the NFS mount daemon). See portmap(8) and rpc.mountd(8)
# for further information.
#
All: LOCAL@cnmc

End of File

Network Type: Class C 192.168.0.x /24

Any ideas how to resolve this issue.

Thank you

Hi,

Just of the top of my head, here: could it be that some hosts dont respond to pings?

Maybe a look in sysctl.conf would relveal net.ipv4.icmp_echo_ignore_all = 1 or something to the like...

Thor

Hi Thor

I cannot loclate that file, sysctl.conf. Would implementing a standalone Bind DNS server solve this issue?

Are you trying to resolve local hostnames?
Windows uses netbios for this.
You could add all the ip's and hostnames in the /etc/hosts files on linux, or install samba with winbind support
http://www.zulius.com/how-to/resolve...es-from-linux/

Kind regards

Doubtfull. Of course, you could just enter this line at the console

and the ping should (mileage may vary) be re-esctablished. Alternatively, how about adding this line to /etc/rc.conf instead?

No Luck

...hmm, that's not a lot. So, what happens if you ping, what's the reply. IP addresses/netmasks? Did it work before? what's the history?

Just because we're at it...try to ping one of the "silent boxes" directly, via their IP address.

By the way, does the IP come up in the ARP cache?

Yes I am trying to resolve just local LAN host by their local hostnames example: server1. Also note: this is an Ubuntu Desktop 11.x 32bit Edition newly install 2 weeks ago via offical Ubuntu.org site.

okay, let's see if they can be reached somehow. Could you (just as proof of concept) ping one via its IP address, not the name?

Use samba, or add the ip's to
/etc/hosts, if they are fixed.

Kind regards