Skip to Content

A stick figure smiling

Here's a preview from my zine, Bite Size Networking!! If you want to see more comics like this, sign up for my saturday comics newsletter or browse more comics!

browse more comics! get the zine!
read the transcript!

nmap lets you explore a network

which ports are open?
what hosts are up?
security people use it a lot!

find which hosts are up

$ nmap-sn
168 is my home network
-sn means “ping scan”. (not -s-n it’s -sn)

just finds hosts by pinging every one, doesn’t port scan

aggressive scan

nmap -v -A
-A = aggressive
port, server version, even OS


skip doing a ping scan and assume every host is up. good if hosts block ping (lots do)

fast port scan

$ nmap -SS-F

just sends a SYN packet to check if each port is open.

I found out which ports my printer has open!

80 http 
443 https 
515 printer
631 ipp 
9100 jetdirect


scan less ports: just the most common ones

-T4 or -T5

scan faster by timing out more quickly

♡ check TLS version and ciphers ♡

check if your server still supports old TLS versions

$ nmap
--script ssl-enum-ciphers
-p 443

list all scripts with:
$ nmap --script-help '*'

Saturday Morning Comics!

Want another comic like this in your email every Saturday? Sign up here!

I'll send you one of my favourite comics from my archives every Saturday.
© Julia Evans 2021 | All rights reserved (see the FAQ for notes about licensing)