unable to ping or ssh in ubuntu 9.04
Hi,
I was using ubntu 9.04 by dual booting it inside windows(WUBI) but then i installed it outside windows as an independent OS. Earlier ping and ssh all were working fine but now neither ping nor ssh work. 1)ping google.com says "ping:unknown host google.com" 2)ssh 10.20.5.2 says "could not resolve the hostname" (which is a local ssh server of my college.) what i dont understand is that when i had installed it inside windows(WUBI) it was working perfectly but now when i have installed it outside ping ssh sftp and mail client too have stopped working...I am able to browse the internet though(with ease).Could that be the source of the error !!!! If i ssh with the name of the server the error returned is could not resolve the hostname. If I rather give the ip addr of the server then the request times out. Also i am behind a squid proxy server for external net access. I have just switched on to linux. Hope somebody can help me.... |
Hi Zagg,
From what I know of WUBI is that it will install Ubuntu on your system from a Windows installer. De end result however is the same as a normal installation. With regards to your problem: It seems to me that you have a problem with your name resolution. When you use DHCP check if a DNS server is provided (cat /etc/resolv.conf) and also if that DNS server is set to resolve names other than it's own domain. If you have a static ip than check if the correct DNS server is set (cat /etc/resolv.conf). Here a short example: Code:
domain example.com Hope this helps and have fun with Ubuntu. It's realy great ;-) |
thanks a lot
Hi timvandijk039,
Thanx a lot for being so informative. Earlier I was using dns server's ip as(statically set) '10.10.2.1' and '10.10.1.2' as these work fine on my friend's laptop. I just changed the entry '10.10.1.1' to it and now its working like a magic.. I would like to know why the same dns ip work for my friends but not for me. Anyways thanks again for solving it.... Although I still cant ping to system outside my campus like google..... |
Not sure why the DNS servers 10.10.2.1 and 10.10.1.2 aren't working. But because you also pointed out that you couldn't ping Google outsite your campus you could be dealing with one or more firewalls.
For DNS, UDP port 53 (some tools use tcp port 53) must be open on the firewall. For ping the firewall needs to allow the ICMP protocol. (ICMP type 8 for the ping to the remote host and type 0 for the response). Happy hacking ;-) |
Without more info of your network, this is hard to say.
ipaddress, netmask, route, .... Which ditribution? post the output from Quote:
Code:
ping 74.125.127.100 Does your ip has the permission to go outside the network? Are the ip's assigned by DHCP? Do they use a proxy? Hence, are you allowed to use the network? Are there restrictions on MAC address in the firewall? ... |
For the ssh client, look at the VerifyHostKeyDNS option in /etc/ssh/ssh_config. There is a similar setting "UseDNS" for the server as well, but I don't know if you control the server as well.
It is not uncommmon for network admins to have pings dropped. To test name resolution, you could try "getent hosts <domain name>". It will resolve hosts in /etc/hosts or use DNS if your /etc/nsswitch.conf and /etc/host.conf files are configured properly. Another thing that can cause delays or lookup problems is IP v6. If your previous install didn't use it but your new install does, in an IPv4 only environment, you can have delays waiting for IPv6 lookups to timeout. |
more info...
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Can your friend ping outside the network? --- no, he cant ping as well.. Quote:
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Code:
:~$ ifconfig Code:
:~$ cat /etc/resolv.conf now i m getting how should i ask questions correctly... |
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