Master Common Network Commands: Detailed Ping, ARP, Tracert, and Route Usage

Ping Command

Ping is a versatile TCP/IP utility used to test connectivity, resolve hostnames, and infer the remote operating system from the TTL value.

Basic usage : ping <IP_or_hostname> sends four echo requests by default.

Interpretation of output :

bytes : size of the ICMP packet.

time : round‑trip latency; smaller values indicate faster response.

TTL : Time‑To‑Live; helps guess the remote OS (e.g., Windows vs. Linux).

Continuous ping : ping -t <IP> runs until interrupted with Ctrl+C, then summarizes packets sent/received.

Specify count : ping -n 10 <IP> sends ten packets and reports min/avg/max times.

Set packet size : ping -l 65500 -t <IP> sends large packets; Windows caps size at 65500 bytes, and misuse can cause denial‑of‑service attacks.

Record route : ping -r 9 <IP> records up to nine hops.

ARP Command

ARP (Address Resolution Protocol) maps an IPv4 address to a MAC address, essential for layer‑2 communication.

Display cache : arp -a lists IP‑to‑MAC mappings.

Add static entry : arp -s <IP> <MAC> binds a MAC address to an IP, useful for preventing IP conflicts.

Delete entry : arp -d <IP> removes a specific cache entry; arp -d * clears the entire table (requires disabling network traffic).

Tracert Command

Tracert traces the route packets take to a destination, revealing each hop.

Basic syntax : tracert <IP_or_hostname>.

Suppress name resolution : tracert -d baidu.com shows only IP addresses.

Limit maximum hops : tracert -h 3 baidu.com stops after three hops.

Set timeout per hop : tracert -w 6 baidu.com waits six milliseconds for each reply.

Route Command

Route displays and manipulates the IP routing table, allowing control over which interface handles specific subnets.

View table : route print shows current routes, including default gateways (0.0.0.0).

Add a static route :

route add 49.222.151.207 mask 255.255.255.255 0.0.0.0 metric 1

(example for an external gateway).

Add a subnet route for internal network : route add 10.168.0.0 mask 255.255.255.0 10.168.1.1 metric 1 directs traffic for 10.168.* to the internal NIC.

Delete a route : route delete <destination>.

By combining these commands, network engineers can quickly diagnose connectivity loss, IP conflicts, slow responses, and configure dual‑NIC environments without repeatedly unplugging cables.

Article sourced from 计算科学与信息化 (reprinted with permission).