ping And nmap problem.

bruse · 11-27-2005, 06:47 AM

I am connected to internet by an proxy server in my university.
I can not ping the 64.233.187.99(www.google.com) or nmap it

[hall4@HallfourServer hall4]$ ping 64.233.187.99
PING 64.233.187.99 (64.233.187.99) 56(84) bytes of data.

--- 64.233.187.99 ping statistics ---
22 packets transmitted, 0 received, 100% packet loss, time 21017ms

[hall4@HallfourServer hall4]$ nmap 64.233.187.99

Starting nmap V. 3.00 ( www.insecure.org/nmap/ )
Note: Host seems down. If it is really up, but blocking our ping probes, try -P0
Nmap run completed -- 1 IP address (0 hosts up) scanned in 54 seconds
[hall4@HallfourServer hall4]$

But the IP address is working well When i put it in mozilla browser.
Browser can resolve it.But Why does i can not ping or nmap it.?
Is there any way?

fouldsy · 11-27-2005, 06:56 AM

What nameservers do you have listed under /etc/resolv.conf?

white scorpion · 11-27-2005, 07:15 AM

They've probably blocked incoming ICMP packets at your university. This means that you can send a ping packet to google, but you will never see the result of it.

this is exactly what you see nmap returns:

Quote:

Note: Host seems down. If it is really up, but blocking our ping probes, try -P0
Nmap run completed -- 1 IP address (0 hosts up) scanned in 54 seconds

try the following: nmap -P0 www.google.com

This should work since it now doesn't use a ping first to determine if the host is up.

bruse · 11-27-2005, 07:50 AM

Yes it detects But it takes lots of time.Why?
Is there any way to fast scan.?

white scorpion · 11-28-2005, 07:31 AM

There are several scanning options for nmap. You can also specify the timeout for a connection.
Please read nmap's helpfile (man nmap / nmap) for more info on this, it is too much for me to explain here.