IP Protocol

• Classi di Reti inet4

/8      /255.0.0.0              16,777,215      Chiamata classe A
/16     /255.255.0.0            65,535          Chiamata classe B
/17     /255.255.128.0          32,767
/18     /255.255.192.0          16,383
/19     /255.255.224.0          8,191
/20     /255.255.240.0          4,095
/21     /255.255.248.0          2,047
/22     /255.255.252.0          1,023
/23     /255.255.254.0          511
/24     /255.255.255.0          255             Chiamata classe C
/25     /255.255.255.128        127
/26     /255.255.255.192        63
/27     /255.255.255.224        31
/28     /255.255.255.240        15
/29     /255.255.255.248        7
/30     /255.255.255.252        3

• pingare tutti gli ip di una rete classe A 192.168.1.255

for a in `seq 1 254`; do echo -n -e "\r   $a   ";ping -c1 192.168.1.$a|grep "bytes from "; done

ping -b  192.168.1.0

• dump packets contents:

tcpdump -nq -s 0 -A -vvv -i eth0 port 5060

• dumping with ngrep examples:

ngrep -qt -W byline port 5060
ngrep -d any port 5060 -W byline > outfile.txt
ngrep -q '8005551212' -W byline port 5060 #<swk>:  only shows packets on 5060 with 8005551212 inside the payload

• capture IPsec traffic for debugging:

tcpdump -i eth0 -n -s 0 -vv \(port 500 or port 4500 or proto 50\)