Why some users have IP's like 192.168.xx.xx ?

[linuxhata]

Followed by "normal" IP? They are on same netblock as server? or what?

[steverobbins]

Hi there,

It means they are on an internal network behind a NAT (Network address translation) firewall that corporations or people who run home networks use to share a single external IP address account with more than one computer.  The other address is the true routable IP address on the internet that identifies the gateway of the network.  You could trace the external IP address with reverse DNS lookup and then you could trace the internal IP address by having access to the internal network.

Best Regards
Steve.