Saturday, April 26, 2008

ISP DHCP research

I have looked into the way Internet Service provider's Dynamic Host Configuration Protocol works as far as I know about such technology, and from my research I concluded: the IP given by your ISP's DHCP will remain to the Media Access Control device.

For example: you have a router connected to the cable modem - this router has a single MAC address therefore you will always have the same external IP, as soon as you change the router (or plug the modem directly to your PC's Network Interface Card) you will get a different external IP. This IP remain the same as long as the NIC's MAC is the same.

Note: these tests were performed on a cable internet service by Rogers Communications Inc. in Canada, and do not apply to DSL internet service providers who seem to change external IP often unlike cable internet service providers

Wednesday, April 9, 2008

Set up gateway on a Linux system

on the pc that will be the gateway:

iptables -F --to flush(drop) the firewall

ifconfig eth1(external interface) 142.204.57.31(external ip) netmask 255.255.255.192(subnetmask) up

ifconfig eth4(internal interface) 10.0.0.1(internal ip) netmask 255.255.255.0(subnetmask) up

echo 1 > /proc/sys/net/ipv4/ip_forward

iptables -t nat -A POSTROUTING -o inetrnal interface -j MASQUERADE

An automated script was written a tutorial is posted HERE.

Saturday, April 5, 2008

System information

how to get system information(specifications) from a Linux mechine

/proc/cpuinfo
/proc/meminfo

curretnly looking for how to find out make, model, motherboard manufacturer, CPU type, RAM from a Linux system.