Port Information

IMAGE GALLERY (1)

What are PORTs?

netstat

Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships

This program is mostly obsolete.

Replacement for netstat is ss.

Replacement for netstat -r is ip route.

Replacement for netstat-i is ip -s link.

Replacement for netstat -g is ip maddr.

ss

another utility to investigate sockets.

Recv-Q and Send-Q columns

tell us how much data is in the queue for that socket, waiting to be read (Recv-Q) or sent (Send-Q). In short: if this is 0, everything’s ok, if there are non-zero values anywhere, there may be trouble. If you look closely at the example, you’ll see that two sockets have a Recv-Q with 38 unread bytes in them. We’ll look into those connections once we know what the other columns mean.

# List all interfaces on computer?
cat /etc/services
grep 22 /etc/services

netstat --interfaces
ip a
ip addr show

# Routing table
netstat --route
ip route show

ss --all
ss --tcp --listening --processes
ss --unix src /tmp/.X11-unix/*
ss --tcp --processes | grep ssh

Show summary of each protocol statistics like ip, icmp, tcp, udp

netstat –statistics
ss –summary

What are local and foreign address in netstat?

Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 localhost:59352         0.0.0.0:*               LISTEN

Local and Foreign address are linux sockets and state are socket states

How to print response time with curl?

• --write-out format
• supress curl outptu
  • curl --write-out '%{http_code}' --silent --output /dev/null http://example.com

Demonstrating how SSL -D creates new SOCSKs proxy

watch --interval 0.2 --differences --color 'ss --tcp --processes --numeric'

for i in (seq 10)
    curl --write-out '%{time_total} United States\n' \
       --proxy socks5://127.0.0.1:9055 \
       --silent --output /dev/null \
       http://ifconfig.co/country
    sleep 1
    curl --write-out '%{time_total} Germany\n' \
       --silent --output /dev/null \
       http://ifconfig.co/country
end

Footnotes

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