Cheatsheet¶
Finding Duplicate IP Addresses on the Network¶
- Install arp-scan.
- Run the following command:
$ sudo arp-scan -I eth0 -l | grep 192.168.1.42
$ OR
$ sudo arp-scan -I eth0 -l | grep DUP
192.168.1.92 00:c0:b7:55:f6:1f AMERICAN POWER CONVERSION CORP (DUP: 2)
192.168.1.152 00:1b:00:0f:55:0e Neopost Technologies (DUP: 2)
192.168.1.158 00:14:38:48:75:b7 Hewlett Packard (DUP: 2)
Capturing cupsd Traffic¶
First to get the list of open ports used by cupsd, use netstat:
$ sudo netstat -lntup | grep cupsd
tcp 0 0 0.0.0.0:631 0.0.0.0:* LISTEN 512/cupsd
tcp6 0 0 :::631 :::* LISTEN 512/cupsd
udp 0 0 0.0.0.0:631 0.0.0.0:* 512/cupsd
tcpdump can’t be used so need to use strace here:
$ sudo strace -p 512 -f -e trace=network -s 10000 -o capture.out &
$ sudo lpinfo -v
This will capture the HTTP messages (IPP) received by cupsd.