Panduan Lengkap Troubleshooting Jaringan Linux: Ping, Netstat, Nmap, dan Tools Lainnya

Update: 3 February 2026

Baca: 8 menit

Panduan Lengkap Troubleshooting Jaringan Linux: Ping, Netstat, Nmap, dan Tools Lainnya

Troubleshooting jaringan adalah skill esensial untuk sysadmin dan developer. Linux menyediakan berbagai tools command line yang powerful untuk diagnose masalah network. Artikel ini membahas penggunaan ping, netstat, nmap, dan tools troubleshooting lainnya secara comprehensive.

Basic Connectivity Test

1. Ping Command

Ping adalah tool paling dasar untuk test connectivity.

# Ping ke host/domain
ping google.com

# Ping dengan count spesifik
ping -c 4 google.com

# Ping dengan interval
ping -i 2 google.com    # Setiap 2 detik

# Ping dengan timeout
ping -w 10 google.com   # Stop setelah 10 detik

# Ping dengan packet size
ping -s 1024 google.com

# Flood ping (root only)
sudo ping -f localhost

# Audible ping (bunyi beep saat reply)
ping -a google.com

2. Traceroute

Traceroute melacak route yang dilalui packets.

# Basic traceroute
traceroute google.com

# Traceroute dengan ICMP (bukan UDP)
traceroute -I google.com

# Traceroute dengan TCP port
traceroute -T -p 443 google.com

# Limit hops
traceroute -m 15 google.com

# Atau gunakan tracepath
tracepath google.com

3. MTR (My Traceroute)

MTR menggabungkan ping dan traceroute.

# Install mtr
sudo apt install mtr    # Debian/Ubuntu
sudo dnf install mtr    # Fedora

# Run mtr
mtr google.com

# MTR dengan report mode
mtr --report --report-cycles 10 google.com

# MTR dengan TCP
traceroute -T google.com

Network Interface Tools

4. ifconfig / ip

# List interfaces (modern)
ip addr show

# Atau dengan ifconfig (legacy)
ifconfig

# Detail interface spesifik
ip addr show eth0

# Statistik interface
ip -s link show eth0

# Enable/disable interface
sudo ip link set eth0 up
sudo ip link set eth0 down

# Set IP address
sudo ip addr add 192.168.1.100/24 dev eth0
sudo ip addr del 192.168.1.100/24 dev eth0

# Flush IP addresses
sudo ip addr flush dev eth0

5. ethtool

# Install
sudo apt install ethtool

# Cek link status
sudo ethtool eth0

# Cek statistics
sudo ethtool -S eth0

# Test cable
sudo ethtool -t eth0

# Set speed dan duplex
sudo ethtool -s eth0 speed 1000 duplex full autoneg off

Network Connection Tools

6. netstat

# List semua connections
netstat -a

# List TCP connections
netstat -at

# List UDP connections
netstat -au

# List listening ports
netstat -tulpn

# List dengan PID
sudo netstat -tulpn | grep :80

# Statistics
netstat -s

# Routing table
netstat -r
# atau:
route -n

# Interface statistics
netstat -i

7. ss (Socket Statistics) - Modern Alternative

# List all sockets
ss -a

# List TCP sockets
ss -t -a

# List UDP sockets
ss -u -a

# List listening sockets
ss -tlnp

# List dengan process
ss -tlnp | grep :80

# Summary
ss -s

# Filter by state
ss -t state established

# Filter by connection to specific port
ss -t dst :443

# Show timer info
ss -t -o

8. lsof (List Open Files)

# List network connections
sudo lsof -i

# List TCP
sudo lsof -i TCP

# List specific port
sudo lsof -i :80
sudo lsof -i :443

# List listening ports
sudo lsof -i -P -n | grep LISTEN

# List connections by process
sudo lsof -i -P -n | grep nginx

# List IPv4/IPv6 only
sudo lsof -i 4
sudo lsof -i 6

Port Scanning dan Discovery

9. Nmap

Nmap adalah network scanner yang powerful.

# Install
sudo apt install nmap

# Scan single host
nmap 192.168.1.1

# Scan multiple hosts
nmap 192.168.1.1 192.168.1.2

# Scan range
nmap 192.168.1.1-254

# Scan subnet
nmap 192.168.1.0/24

# Scan dengan port range
nmap -p 1-65535 192.168.1.1

# Scan specific ports
nmap -p 22,80,443 192.168.1.1

# Scan dengan service detection
nmap -sV 192.168.1.1

# OS detection
sudo nmap -O 192.168.1.1

# Aggressive scan
sudo nmap -A 192.168.1.1

# Stealth scan
sudo nmap -sS 192.168.1.1

# UDP scan
sudo nmap -sU 192.168.1.1

# Fast scan (100 ports paling umum)
nmap -F 192.168.1.1

# Scan dari file
nmap -iL hosts.txt

# Output ke file
nmap -oN scan.txt 192.168.1.1
nmap -oX scan.xml 192.168.1.1

# Scan dengan script
nmap --script vuln 192.168.1.1

10. nc (Netcat)

Netcat adalah “Swiss Army Knife” untuk networking.

# Test port connectivity
nc -zv hostname 80
nc -zv google.com 443

# Test multiple ports
nc -zv google.com 80 443 8080

# Create listener
nc -l 8080

# Create reverse shell (hati-hati!)
nc -e /bin/bash -l 8080

# Send file
nc -w 3 hostname 8080 < file.txt

# Receive file
nc -l 8080 > received_file.txt

# Port scan
nc -zv 192.168.1.1 1-1024

DNS Tools

11. nslookup

# Query DNS
nslookup google.com

# Query specific record
nslookup -query=MX google.com
nslookup -query=NS google.com

# Query specific nameserver
nslookup google.com 8.8.8.8

12. dig

# Basic query
dig google.com

# Query specific record
dig google.com MX
dig google.com NS
dig google.com TXT

# Query dengan detail
dig +trace google.com

# Reverse DNS
dig -x 8.8.8.8

# Query specific nameserver
dig @8.8.8.8 google.com

# Short output
dig +short google.com

# Query semua records
dig google.com ANY

13. host

# Simple DNS lookup
host google.com

# Lookup specific type
host -t MX google.com

# Reverse lookup
host 8.8.8.8

14. whois

# Install
sudo apt install whois

# Lookup domain info
whois google.com

# Lookup IP info
whois 8.8.8.8

Advanced Network Tools

15. tcpdump

# Install
sudo apt install tcpdump

# Capture semua packets
sudo tcpdump

# Capture di interface spesifik
sudo tcpdump -i eth0

# Capture dengan filter
sudo tcpdump -i eth0 port 80
sudo tcpdump -i eth0 host 192.168.1.100
sudo tcpdump -i eth0 src 192.168.1.100
sudo tcpdump -i eth0 dst 192.168.1.100

# Capture dan save ke file
sudo tcpdump -w capture.pcap

# Read dari file
sudo tcpdump -r capture.pcap

# Capture dengan verbose
sudo tcpdump -v
sudo tcpdump -vv
sudo tcpdump -vvv

# Capture limit
sudo tcpdump -c 100

# Capture dengan timestamp
sudo tcpdump -tttt

# Filter protocol
sudo tcpdump icmp
sudo tcpdump tcp
sudo tcpdump udp

# Complex filter
sudo tcpdump 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)'

16. Wireshark / tshark

# Install
sudo apt install wireshark tshark

# Capture dengan tshark
sudo tshark -i eth0

# Capture dengan filter
sudo tshark -i eth0 port 80

# Capture ke file
sudo tshark -w capture.pcap

# Read file
sudo tshark -r capture.pcap

17. nload

# Install
sudo apt install nload

# Monitor traffic
sudo nload

# Monitor interface spesifik
sudo nload eth0

18. iftop

# Install
sudo apt install iftop

# Monitor bandwidth usage
sudo iftop

# Monitor interface spesifik
sudo iftop -i eth0

# Monitor port spesifik
sudo iftop -f "port 80"

19. bmon

# Install
sudo apt install bmon

# Monitor dengan grafik
sudo bmon

# Export ke file
sudo bmon -o ascii > bandwidth.log

Routing Tools

20. route / ip route

# Show routing table
ip route show
# atau:
route -n

# Add route
sudo ip route add 192.168.2.0/24 via 192.168.1.1

# Delete route
sudo ip route del 192.168.2.0/24

# Default route
sudo ip route add default via 192.168.1.1

# Show specific route
ip route get 8.8.8.8

21. arp

# Show ARP table
ip neigh show
# atau:
arp -a

# Delete ARP entry
sudo ip neigh del 192.168.1.100 dev eth0

# Flush ARP cache
sudo ip neigh flush all

Firewall Tools

22. iptables

# List rules
sudo iptables -L
sudo iptables -L -v -n

# List dengan line numbers
sudo iptables -L --line-numbers

# List specific table
sudo iptables -t nat -L
sudo iptables -t mangle -L

# Monitor packets
sudo iptables -A INPUT -j LOG

# Clear all rules
sudo iptables -F
sudo iptables -X
sudo iptables -t nat -F
sudo iptables -t nat -X

23. nftables

# List ruleset
sudo nft list ruleset

# List table spesifik
sudo nft list table inet filter

# Monitor
sudo nft monitor

WiFi Tools

24. iw / iwconfig

# List wireless devices
iw dev

# Scan networks
sudo iw dev wlan0 scan

# Connect (gunakan NetworkManager atau wpa_supplicant untuk full connection)

# Show wireless link
iw dev wlan0 link

# Legacy: iwconfig
iwconfig
iwconfig wlan0

25. wavemon

# Install
sudo apt install wavemon

# Monitor WiFi signal
sudo wavemon

Network Testing Scripts

Script: Complete Network Diagnose

#!/bin/bash
# network-diagnose.sh

HOST="$1"

if [ -z "$HOST" ]; then
    echo "Usage: $0 <hostname/IP>"
    exit 1
fi

echo "========================================"
echo "Network Diagnose Report for: $HOST"
echo "Date: $(date)"
echo "========================================"

echo -e "\n--- Basic Connectivity ---"
ping -c 4 "$HOST"

echo -e "\n--- Route Trace ---"
traceroute -m 15 "$HOST" 2>/dev/null || tracepath "$HOST" 2>/dev/null

echo -e "\n--- DNS Resolution ---"
dig +short "$HOST"

echo -e "\n--- Port Scan (Top 20) ---"
nmap -F "$HOST" 2>/dev/null || echo "nmap not installed"

echo -e "\n--- Report Complete ---"

Script: Monitor Network Health

#!/bin/bash
# network-monitor.sh

LOGFILE="/var/log/network-health.log"
HOSTS=("8.8.8.8" "1.1.1.1" "google.com")

for host in "${HOSTS[@]}"; do
    if ping -c 1 -W 2 "$host" > /dev/null 2>&1; then
        echo "[$(date)] $host: UP" >> "$LOGFILE"
    else
        echo "[$(date)] $host: DOWN" >> "$LOGFILE"
    fi
done

Troubleshooting Common Network Issues

1. No Internet Connectivity

# 1. Cek interface
ip addr show

# 2. Cek gateway
ip route | grep default

# 3. Test gateway
ping $(ip route | grep default | awk '{print $3}')

# 4. Test DNS
ping 8.8.8.8

# 5. Cek DNS resolution
dig google.com

# 6. Cek resolv.conf
cat /etc/resolv.conf

# 7. Restart networking
sudo systemctl restart NetworkManager
# atau:
sudo systemctl restart networking

2. Slow Network

# 1. Test speed dengan iperf3
sudo apt install iperf3
iperf3 -c iperf.he.net

# 2. Cek bandwidth usage
sudo iftop -i eth0

# 3. Cek errors
ip -s link show eth0

# 4. Test dengan mtr
mtr --report google.com

# 5. Cek duplex/speed
sudo ethtool eth0

3. Connection Refused

# 1. Cek apakah service running
sudo systemctl status nginx

# 2. Cek listening ports
sudo ss -tlnp | grep :80

# 3. Test dengan nc
nc -zv localhost 80

# 4. Cek firewall
sudo iptables -L | grep 80
sudo ufw status | grep 80

# 5. Check logs
sudo tail -f /var/log/nginx/error.log

4. DNS Not Working

# 1. Cek resolv.conf
cat /etc/resolv.conf

# 2. Test dengan dig
dig @8.8.8.8 google.com

# 3. Cek DNS service
sudo systemctl status systemd-resolved

# 4. Flush DNS cache
sudo systemd-resolve --flush-caches

# 5. Test hosts file
ping localhost
cat /etc/hosts

Kesimpulan

Troubleshooting jaringan Linux memerlukan kombinasi tools yang tepat dan pemahaman tentang networking concepts. Dengan menguasai tools di atas, Anda bisa:

Diagnose connectivity issues dengan ping, traceroute, mtr
Analyze network traffic dengan tcpdump, wireshark
Scan dan audit network dengan nmap, nc
Monitor performance dengan nload, iftop, bmon
Troubleshoot DNS dengan dig, nslookup
Manage firewall dengan iptables, nftables

Latihan secara regular dengan scenario troubleshooting untuk mempertajam skill Anda. Network troubleshooting adalah skill yang selalu berguna dalam karir IT apapun.