Acronyms and Command-Line Tool Quick Table
Key Takeaways
- Acronyms are easier to retain when tied to where they appear in a troubleshooting workflow.
- Command-line tools map to layers: local configuration, name resolution, path testing, port testing, and packet inspection.
- Use ipconfig, ifconfig, or ip to verify local addressing before chasing remote services.
- Use ping and traceroute carefully because ICMP may be blocked even when applications work.
- Use nslookup or dig for DNS, arp for local neighbor mapping, and netstat or ss for listening ports and sessions.
Last updated: April 2026
Acronyms and Command-Line Tools
Network+ acronym questions are usually scenario questions in disguise. A prompt may not ask "What does DHCP mean?" Instead, it may say a client has APIPA and ask which service or tool to check.
Acronym Quick Table
| Acronym | Meaning | Fast association |
|---|---|---|
| ACL | Access control list | Permit or deny traffic |
| AP | Access point | Wireless network device |
| ARP | Address Resolution Protocol | IPv4-to-MAC mapping on a local network |
| BGP | Border Gateway Protocol | Internet and external routing |
| CIDR | Classless Inter-Domain Routing | Prefix notation such as /24 |
| DHCP | Dynamic Host Configuration Protocol | Automatic IP address assignment |
| DNS | Domain Name System | Names to IP addresses |
| FHRP | First Hop Redundancy Protocol | Gateway redundancy concept |
| HSRP | Hot Standby Router Protocol | Cisco gateway redundancy protocol |
| IDS | Intrusion detection system | Alerts on suspicious activity |
| IPS | Intrusion prevention system | Blocks or prevents suspicious activity |
| LDAP | Lightweight Directory Access Protocol | Directory queries |
| MTU | Maximum transmission unit | Largest frame or packet payload size before fragmentation behavior matters |
| NAC | Network access control | Places users or devices based on identity or posture |
| NAT | Network Address Translation | Address translation, often private to public |
| NTP | Network Time Protocol | Time synchronization |
| OSPF | Open Shortest Path First | Link-state interior routing |
| PoE | Power over Ethernet | Power and data on twisted pair |
| RADIUS | Remote Authentication Dial-In User Service | AAA for VPN, Wi-Fi, and network access |
| SNMP | Simple Network Management Protocol | Monitoring and device management |
| STP | Spanning Tree Protocol | Loop prevention at Layer 2 |
| VLAN | Virtual LAN | Layer 2 segmentation |
| VPN | Virtual private network | Encrypted tunnel over untrusted network |
| VRF | Virtual routing and forwarding | Separate routing tables |
Command-Line Tool Table
| Tool | Platform | Use |
|---|---|---|
| ipconfig | Windows | View or renew IP configuration |
| ifconfig | Linux/macOS legacy | View interface configuration |
| ip | Linux | View and change addresses, routes, and links |
| ping | Most | Basic reachability and latency check using ICMP |
| traceroute | Linux/macOS | Path discovery toward destination |
| tracert | Windows | Windows path discovery |
| nslookup | Most | DNS lookup testing |
| dig | Linux/macOS and installed tools | Detailed DNS queries |
| arp | Most | View local IPv4-to-MAC neighbor cache |
| netstat | Most | Connections, listening ports, and statistics |
| ss | Linux | Modern socket statistics replacement for many netstat uses |
| route | Most legacy | View or change routing table |
| netsh | Windows | Network configuration and troubleshooting |
| Wireshark | GUI | Packet capture and analysis |
| Packet capture CLI | Linux/macOS or installed tools | Capture traffic from a terminal when authorized |
| nmap | Installed tool | Port scanning and service discovery when authorized |
| curl | Most | Test HTTP, HTTPS, and other URL-based services |
| ssh | Most | Secure remote administration |
Tool Selection Workflow
| Question | Tool examples |
|---|---|
| Does the client have a valid IP, mask, gateway, and DNS server? | ipconfig, ip addr, ip route |
| Does the name resolve correctly? | nslookup, dig |
| Is the destination reachable at Layer 3 where ICMP is allowed? | ping |
| Where does the path stop? | traceroute, tracert |
| Is the service port open? | netstat, ss, nmap when authorized, curl for web |
| What is actually on the wire? | Packet capture CLI, Wireshark |
Mini Scenarios
| Symptom | First useful tool |
|---|---|
| Windows client has no network access | ipconfig /all |
| Linux server may have wrong default route | ip route |
| Website fails only by name | nslookup or dig |
| Suspected blocked HTTPS service | curl, port test, firewall logs |
| Suspected duplicate IP on local LAN | arp table, switch MAC table |
Common Traps
- Running traceroute before checking whether the host has a valid IP configuration.
- Assuming ping failure proves the application is down.
- Using nmap or packet capture without authorization in a real environment.
- Forgetting that DNS can return the wrong address even when the DNS server responds.
- Confusing ARP for local IPv4 neighbor mapping with DNS name resolution.
- Treating a command name as universal when flags differ by operating system.
Test Your Knowledge
Which tool is most directly used to test DNS name resolution?
A
B
C
D
Test Your Knowledge
A Linux server may have the wrong default gateway. Which command family is most appropriate?
A
B
C
D
Test Your KnowledgeMulti-Select
Which tool-to-purpose matches are correct? Select three.
Select all that apply
arp for local IPv4-to-MAC cache
traceroute or tracert for path discovery
Packet capture CLI or Wireshark for packet capture
DNS for measuring cable length directly
PoE for resolving hostnames