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monitor network traffic and throughput in real time
see http://iptraf.seul.org/ for all kinds of documentation and screenshots

parted - scripted partitioning (of all multipathed SAN LUNs)
`multipath -ll` requires Device Mapper multipath.conf configuration. And of course, replace "3PARdata,VV" with your disk array's SCSI vendor,LUN name. - GPT partition table allows you to create >2TB partitions

Force unmount occupied partition
Alternative if "Lazy unmount" (umount -l) doesn't obey. Alternative for NFS: $ umount -f /media/sdb1 Use with caution: forcing to unmount a busy partition can cause data loss!

Get your external IP address ( 10 characters long )
Shortest url to a external IP-service, 10 characters.

send echo to socket network
this command will send a message to the socket 25 on host 192.168.1.2 in tcp. works on udp and icmp understand only IP address, not hostname. on the other side (192.168.1.2), you can listen to this socket and test if you receive the message. easy to diagnose a firewall problem or not.

Print a list of installed Perl modules
This version works on an AIX system on which I have very limited permissions. The other version fails with "Can't open file /usr/opt/perl588/lib/site_perl/5.8.8/aix/auto/DBI/.packlist".

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Get IP from hostname

ping MAC ADDRESS
# first install arp-scan if not have it arp-scan 10.1.1.0/24 .... show ip+mac in localnet awk '/00:1b:11:dc:a9:65/ {print $1}' .... get ip associated with MAC ` backtick make do command substitution passing ip to command ping

ssh to machine behind shared NAT
Useful to get network access to a machine behind shared IP NAT. Assumes you have an accessible jump host and physical console or drac/ilo/lom etc access to run the command. Run the command on the host behind NAT then ssh connect to your jump host on port 2222. That connection to the jump host will be forwarded to the hidden machine. Note: Some older versions of ssh do not acknowledge the bind address (0.0.0.0 in the example) and will only listen on the loopback address.


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