Network Tools

Network diagnostic and testing tools for TCP, UDP, HTTP, and DNS

TCP & UDP

arp && arping

# install
apt install net-tools
apt install arping

# select arp table
arp -ne
-e                       display (all) hosts in default (Linux) style
-n, --numeric            don\'t resolve names

# arping
arping 192.168.1.100
-c count
-i interface
-s MAC
-S IP
# get packets
tcpdump -ttttnvvvS -i ens160 arp

hping3 && tcping

# hping3 = apt install hping3
## Docker = utkudarilmaz/hping3
# imitate syn flood
hping3 -S -p 8877 --flood 127.0.0.1

# multicast
hping3 -1 224.0.0.8 -a 10.0.0.1 -c 10 -i u1000000


# tcping
## DockerHub
docker pull pouriyajamshidi/tcping
# GitHub container registry
docker pull ghcr.io/pouriyajamshidi/tcping:latest

iftop

# iftop -h
   -n                  dont do hostname lookups
   -N                  dont convert port numbers to services
   -i interface        listen on named interface
   -t                  use text interface without ncurses
   Sorting orders:
   -o 2s                Sort by first column (2s traffic average)
   -o 10s               Sort by second column (10s traffic average) [default]
   -o 40s               Sort by third column (40s traffic average)
   -o source            Sort by source address
   -o destination       Sort by destination address
   The following options are only available in combination with -t
   -s num              print one single text output afer num seconds, then quit
   -L num              number of lines to print

# common
iftop -nN -i ens4 -o 10s
iftop -nN -s 5 -t
iftop -nN -L 5 -t
iftop -F 192.168.1.0/24

# inside keyboard keys
Host display:                          General:
 n - toggle DNS host resolution         P - pause display
 s - toggle show source host            h - toggle this help display
 d - toggle show destination host       b - toggle bar graph display
 t - cycle line display mode            B - cycle bar graph average
                                        T - toggle cumulative line totals
Port display:                           j/k - scroll display
 N - toggle service resolution          f - edit filter code
 S - toggle show source port            l - set screen filter
 D - toggle show destination port       L - lin/log scales
 p - toggle port display                ! - shell command
                                        q - quit
Sorting:
 1/2/3 - sort by 1st/2nd/3rd column
 < - sort by source name
 > - sort by dest name
 o - freeze current order

ip

# apt install iproute2

# select route table
ip route ls
# select info
ip addr ls
ip link ls

# add ip to tun0，do not conflict other link
ip addr add 172.31.0.1/24 dev tun0
# startup tun0 link and add route table to 172.31.0.1/24
ip link set tun0 up


### namespace
# select namespace list
ip netns list
# add netns(in /var/run/netns/)
ip netns add net-test1
# exec in netns
ip netns exec net-test1 ip addr
# ip netns exec ns1 /bin/bash --rcfile <(echo "PS1=\"namespace net-test1> \"")
ip netns exec net-test1 ip link set lo up

# veth pair
# execute in host
ip link add br0 type bridge
ip link set dev br0 up
ip netns add net0
ip netns add net1
ip link add veth-a0 type veth peer name veth-net0
ip link set dev veth-net0 master br0
ip link set dev veth-net0 up
ip link add veth-b0 type veth peer name veth-net1
ip link set dev veth-net1 master br0
ip link set dev veth-net1 up

# execute in net0
ip link set dev veth-a0 netns net0
ip netns exec net0 ip link set dev veth-a0 name eth0
ip netns exec net0 ip addr add 10.0.1.2/24 dev eth0
ip netns exec net0 ip link set dev eth0 up
# execute in net1
ip link set dev veth-b0 netns net1
ip netns exec net1 ip link set dev veth-b0 name eth0
ip netns exec net1 ip addr add 10.0.1.3/24 dev eth0
ip netns exec net1 ip link set dev eth0 up
# verify
ip netns exec net0 ping -c 3 10.0.1.3

netstat && ss

# netstat = apt install net-tools
# count all tcp state number
netstat -tna | awk '/tcp/ {++S[$NF]} END {for(a in S) print a, S[a]}'


# ss = apt install iproute2
# count all tcp state number
ss -na | awk '/tcp/ {++S[$2]} END {for(a in S) print a, S[a]}'

# select all tcp connect
ss -tnap

# force kill tcp connect
ss -K dst 1.1.1.1 dport = 57156

nc && netcat

# install
apt install netcat-openbsd

# listen and test
nc -l 9999 -k -c 'xargs -n1 echo'

# post
echo -e "POST /post HTTP/1.1\r\nHost: httpbin.org\r\nContent-Type: application/x-www-form-urlencoded\r\nContent-Length: 7\r\n\r\na=1&b=2\r\n" |nc 172.22.3.29 8877

tcpdump

# install
apt install tcpdump

# Listen on interface
-i interface
# Don't convert address
-n
# Print absolute, rather than relative, TCP sequence numbers
-S
# Don't print a timestamp on each dump line
-t
# Print the timestamp, as seconds since January 1, 1970, 00:00:00, UTC
-tt
# Print a delta (micro-second resolution) between current and previous line on each dump line
-ttt
# Print a timestamp, as hours, minutes, seconds, and fractions of a second since midnight, preceded by the date, on each dump line
-tttt
# Print a delta (micro-second resolution) between current and first line on each dump line.
-ttttt
# Even more verbose output
-v
-vv
-vvv
# Write the raw packages to file
-w file


# rotate every 100M and reserved 20
tcpdump -i eth0 port 8880 -w cvm.pcap -C 100 -W 20
# rotate every 120s and suffix
tcpdump -i eth0 port 31780 -w node-%Y-%m%d-%H%M-%S.pcap -G 120

# protocol
tcpdump [ip|tcmp|tcp|udp|proto 112]
tcpdump 'tcp[tcpflags] & (tcp-syn|tcp-fin) != 0'
tcpdump -i ens4 -nStttv icmp and src 1.1.1.1

# source ip or dest ip
tcpdump src 1.1.1.1 or dst 1.1.1.1

# port
tcpdump not port 80

# fileter timeout packet
tcpdump -r test.pcap 'tcp[tcpflags] & (tcp-rst) != 0' -nttt

# example
tcpdump -i eth0 -nStttvvv src 1.1.1.1 or dst 1.1.1.1 and port 80

tcpkill

# install
apt install dsniff

tcpkill -i <interface> host <destination_ip> and port <destination_port>
# example
tcpkill -i lo host 127.0.0.1 and port

wscat

# install
npm install wscat -g

wscat -c ws://api.example.com/ws
wscat -c wss://api.example.com/ws --no-check

HTTP

ab && wrk

# install ab
apt install apache2-utils

# use
ab -n 1000 -c 100 http://www.baidu.com


# install wrk
# http://github.com/wg/wrk.git
# use
# -t threads
# -c connections to keep open
# -d duration
wrk -t 100 -c 10000 -d 30 --latency http://www.google.com/

curl

# UserAgent
curl -A 'chrome' https://example.com

# Cookie
curl -b 'foo=bar' https://example.com
curl -c cookie.txt https://example.com

# HTTP GET/POST data
curl -d 'username=abc' -X POST https://example.com/login
curl -d '@data.txt' -X POST https://example.com/login
curl -d '{"username":"abc"}' -H 'Content-Type: application/json' -X POST https://example.com/login
curl --data-binary 'msg=hello wordld' https://example.com/login      # transfer binary data
curl --data-raw 'msg=hello wordld' https://example.com/login         # transfer original data
curl --data-urlencode 'msg=hello wordld' https://example.com/login   # URL Encode data

# HTTP Referer
curl -e 'https://google.com?q=example' https://example.com
curl -H'Referer: https://google.com?q=example' https://example.com


# HTTP GET data
curl -G -d 'q=query' -d 'count-10' https://example.com/search

# HTTP Header
curl -H'Accept-Language: en-US' -H 'Content-Type: application/json' https://example.com

# HTTP HEAD request
curl -I https://example.com

# Skip SSL check
curl -k https://example.com

# Follow request
curl -L https://example.com

# Limit rate request
curl --limit-rate 200k https://example.com

# Save to file
curl -o example.html https://example.com
curl -O https://example.com/foo/bar.html

# Silence
curl -s https://example.com
curl -S https://example.com    # only error msg

# Server user and password
curl -u 'user:pwd' https://example.com/login
curl -H'Authorization: Basic cHdkCg==' https://example.com/login
curl https://user:[email protected]/login

# Verbose info
curl -v https://example.com
curl --trace https://example.com

# HTTP request proxy
curl -x [protocol://]host[:port] https://example.com
curl -x socks5://user:[email protected]:8080 https://example.com

# HTTP method
curl -X [GET|POST|PUT|DELETE|OPTIONS] https://example.com

#######
# Example
#######
# 304 response
curl https://cdn.example.com/ -H'if-modified-since: Mon, 1 Jan 2024 00:00:00 GMT' -i
curl https://cdn.example.com/ -H'if-none-match: "xxx123-xxx456"' -i

# check tls max version
curl https://google.com -kv --tlsv1 --tls-max 1.0
curl https://google.com -kv --tlsv1.3 --tls-max 1.3

# special resolve IP before local DNS resolve
curl https://google.com --resolve google.com:443:1.1.1.1 -v

# tls certificate
openssl s_client -servername your.domain.com -connect 127.0.0.1:443

# mock websocket request
curl http://127.0.0.1:9999 -H'Upgrade: websocket' -H'Connection: Upgrade' -H'Sec-WebSocket-Key: eeZn6lg/rOu8QbKwltqHDA==' -H'Sec-WebSocket-Version: 13'

# timing
curl -L -w "time_namelookup: %{time_namelookup}\ntime_connect: %{time_connect}\ntime_appconnect: %{time_appconnect}\ntime_pretransfer: %{time_pretransfer}\ntime_redirect: %{time_redirect}\ntime_starttransfer: %{time_starttransfer}\ntime_total: %{time_total}\n" https://example.com/
###
time_namelookup: %{time_namelookup}
time_connect: %{time_connect}
time_appconnect: %{time_appconnect}
time_pretransfer: %{time_pretransfer}
time_redirect: %{time_redirect}
time_starttransfer: %{time_starttransfer}
time_total: %{time_total}
###

DNS

dig

# normal query
dig www.google.com
dig -t ns www.google.com
dig -t cname www.google.com

# query dns request from root dns server
dig +trace www.google.com

# query dns request only ip information
dig +short www.google.com
# query dns request only resolve information
dig +noall +answer www.google.com

# query dns request from specific dns server
dig www.google.com @8.8.8.8

# reverse lookups
dig -x 8.8.8.8

# get local dns server external ip
dig +short TXT whoami.ds.akahelp.net
"ns" "123.126.xx.xx" # ns: the DNS egress IP address used by the local machine
"ecs" "120.52.xx.xx/32/24" # ecs (EDNS-client-subnet): the client subnet carried in the query request
"ip" "123.126.xx.xx" # ip: the client representative IP selected by the authoritative nameserver from ecs, LocalDNS does not carry the real client IP for privacy

# get local dns server ip address
dig xxx.debug.danuoyi.tbcache.com

# query dns request with specific EDNS client subnet
dig www.google.com +subnet=1.1.1.0/24

Reference:

1. curl Manual

2. tcpdump Manual

3. iproute2