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
route add 127.0.0.1
route add -net 192.168.1.0 gw 192.168.1.99 dev eth1
route add -net 192.168.20.0 gw 192.168.20.99 dev eth0
route add default gw 192.168.1.252

route add default gw 10.9.63.1 metric 10
================================================== 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
================================================== tcpdump
------	monitor all traffic except current ssh connection
tcpdump -i eth0 -nN -vvv -xX -s 1500 port not 22

------	filter out port 123 with the full length of the packet, (-s 0)
tcpdump -i eth0 -nN -vvv -xX -s 0 port not 22  and port not 123

------	filter only a certain host say 192.168.5.11
tcpdump -i eth0 -nN -vvv -xX  port not 22 and host 192.168.5.11

------	Collect IP addresses and 20 packets.
tcpdump -i eth0 -nN  -s 1500 port not 22 -c 20

------	Watch for DOS attacks, (show only the SYN packets on all interfaces)
tcpdump 'tcp[13] & 2 == 2'

================================================== 
http://oob.freeshell.org/nzwireless/nocat1.html
http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux
http://bayareafreefi.com
http://www.wca.org
=================================
iwconfig <interface> essid <essid>
iwconfig eth0 essid tsunami key 3959387282...
alias connect='iwconfig eth0 essid tsunami key 495jwkdhj83764'

=================================
WAP - Wireless Access Point
WPA - Wi-Fi Protected Access
PSK - Pre-Shared Key
TKIP - Temporal Key Integrity Protocol
EAP - Extensible Authentication Protocol
EAP-MD5 - MD5-hash-based credentials (poor chice for 802.1x auth in WPA context)
EAP-TLS - TLS (descendant of SSL) encrypt. protocol; strong: uses digital certs.
PEAP - Protected EAP (Microsoft, weak auth for MD5 and MS-CHAP) MS centric!
EAP-TTLS - non-MS drivenalternative to PEAP.
LEAP - Cisco Lightweight EAP
EAP-SIM - MS's EAP-MSCHAPv2

PKI - Public Key Infrastructure

WPA (Protocols)
 |
 |---> Authentication: 802.1x
 |          |
 |          |---> EAP-TLS
 |          |---> EAP-MD5
 |          |---> PEAP
 |          |---> EAP-TTLS
 |          |---> (etc.)
 |
 ----> Encryption: TKIP

===== route del
route del -net 169.254.0.0 netmask 255.255.0.0 dev eth0

=====  ipcalc
i=0; for s in $(seq 0  8 255); do let i=i+1; echo -e "-----> subnet: $i\n"; ipcalc -n 192.168.3.$s/29; done > /tmp/ip-8
i=0; for s in $(seq 0 16 255); do let i=i+1; echo -e "-----> subnet: $i\n"; ipcalc -n 192.168.3.$s/28; done > /tmp/ip-16
i=0; for s in $(seq 0 32 255); do let i=i+1; echo -e "-----> subnet: $i\n"; ipcalc -n 192.168.3.$s/27; done > /tmp/ip-32
=====