First load the IP Alias module (you can skip this step if you compiled the module into the kernel): 

       /sbin/insmod /lib/modules/`uname -r`/ipv4/ip_alias.o 

       Second, setup the loopback, eth0 and all the IP #s beginning with the
	main IP # for the eth0 interface:

       /sbin/ifconfig lo 127.0.0.1
       /sbin/ifconfig eth0 up
       /sbin/ifconfig eth0 172.16.3.1 
       /sbin/ifconfig eth0:0 172.16.3.10
       /sbin/ifconfig eth0:1 172.16.3.100

       172.16.3.1 is the main IP #, while .10 and .100 are the aliases. The
	magic is the eth0:x where x=0,1,2,...n for the different IP #s. The
       main IP # does not need to be aliased.

       Third, setup the routes. First route the loopback, then the net and,
	finally, the various IP #s starting with the default (originally
       allocated) one:

       /sbin/route add -net 127.0.0.0 
       /sbin/route add -net 172.16.3.0 dev eth0
       /sbin/route add -host 172.16.3.1 dev eth0
       /sbin/route add -host 172.16.3.10 dev eth0:0
       /sbin/route add -host 172.16.3.100 dev eth0:1
       /sbin/route add default gw 172.16.3.200

--------------------------------
================================================== Router
/sbin/route add 127.0.0.1
/sbin/route add -net 192.168.1.0 gw 192.168.1.99 dev eth1
/sbin/route add -net 192.168.20.0 gw 192.168.20.99 dev eth0
/sbin/route add default gw 192.168.1.252
================================================== keep ssh alive ?
echo 500 > /proc/sys/net/ipv4/tcp_keepalive_time
sh -c 'while sleep 45; do echo -en " \b"; done' &
================================================== IP-alias
/sbin/insmod /lib/modules/`uname -r`/ipv4/ip_alias.o
/sbin/ifconfig eth0:0 172.16.3.10
/sbin/route add -net 172.16.3.0 dev eth0
/sbin/route add -host 172.16.3.10 dev eth0:0
/sbin/route add default gw 172.16.3.200
================================================== boot
arp -s somehost mac-address pub
ping somehost
--------------------------------
================================================== list open net files
lsof -P | grep ":"
http://oob.freeshell.org/nzwireless/nocat1.html