Key takeaway
Start by checking the device address, mask, gateway and DNS. Consult the network owner’s plan before changing settings.
A network and its main parts
A network combines devices, wired or radio links and shared protocols so data can move between them. A LAN covers a limited area such as a home or office; a MAN covers a city or campus; a WAN spans a wider geography. A WLAN is a wireless LAN, a PAN connects personal devices over a short range, and a VPN tunnels to private resources over a public network. A router forwards packets between IP networks; a switch connects devices within a local segment; an access point connects Wi‑Fi devices to a wired network. A home unit may combine a modem and router, though they perform different jobs.
Router
Forwards packets between networks; some routers also provide DHCP and NAT.
Switch
Connects wired devices on the same local network.
Access point
Lets wireless devices join an existing local network.
IP address, mask and network prefix
An IP address identifies a device interface on a network. In IPv4, the subnet mask marks which bits identify the network and which identify an interface within it; the mask 255.255.255.0 corresponds to a /24 prefix. The address 192.168.1.25/24 belongs to 192.168.1.0/24. In this IPv4 subnet, .0 is the network address, .255 is the broadcast address, and .1–.254 are available for ordinary hosts.
Why networks are divided into subnets
A subnet divides a larger address range into smaller logical segments. For example, a /24 typically has 254 host addresses and a /28 has 14. This helps address planning; guest, IoT, server and payment systems can be placed in separate segments, with firewall rules allowing only required traffic between them. VLANs can support logical separation. Firewalls, network monitoring, IDS/IPS, endpoint protection and updates complement segmentation; being inside the network is not by itself a basis for trust.
DHCP configures a device for the network
DHCP automatically provides a device with an IP address and related settings such as the subnet mask, default gateway, DNS servers and lease duration. An IPv4 exchange commonly follows Discover, Offer, Request and Acknowledge. A home router may serve as the DHCP server; larger networks often use a separate server and a relay for other segments.
Discover
The device looks for a DHCP server on the local network.
Offer
A server offers an address and configuration.
Request
The client requests the offered address.
Acknowledge
The server confirms the assignment and lease.
Dynamic, static and reserved addresses
DHCP is usually convenient for devices such as laptops and phones that move between networks. An administrator may give a server or printer a static address or create a DHCP reservation so it remains reachable at a known address. Plan static addresses alongside the DHCP pool; overlapping assignments can create an IP conflict.
Protect DHCP settings from tampering
A DHCP client receives important settings such as a gateway and DNS resolver along with its address. An unauthorized server could offer a false route or resolver, and a flood of false requests could exhaust the address pool. An administrator can configure DHCP snooping and port controls on a managed switch and compare DHCP snooping events and the server addresses received by clients with the approved server list. On a router, replace the default administrator password, install updates, disable remote administration when it is unnecessary, and place guest/IoT devices in a separate segment. Automatic address assignment does not establish trust.
Inspect addresses on Windows
In Windows Command Prompt, ipconfig shows an active adapter’s IPv4/IPv6 address, mask and default gateway; ipconfig /all also lists DHCP and DNS details. VPN, Wi‑Fi and Ethernet may appear as separate adapters. In IPv4, 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 are private address ranges for use within networks. A public address may be shared by several devices behind router or provider NAT and usually does not appear in ipconfig; confirm it from the router or provider.
ipconfig
ipconfig /all
Troubleshoot connectivity in stages
First check that the adapter is connected and has the expected address, mask, gateway and DNS settings. Then send a limited number of ping requests to the local gateway and a known domain. Replace 192.168.1.1 in the example with your gateway’s address. No Echo reply does not prove a device is powered off: a firewall or network policy may block ICMP. If the address and gateway look right but names do not resolve, inspect DNS; coordinate configuration changes with the administrator.
ping -n 4 192.168.1.1
nslookup example.com
Frequently asked questions
When reading address output, consider the active adapter, network boundary and DHCP role.
Why do I see more than one IP address?
Wi‑Fi, Ethernet, VPN and virtual adapters can each show a different address. Check which active adapter applies to the task.
Does ipconfig show the public address?
Behind NAT, ipconfig usually shows the device’s local adapter address. Confirm the public egress address with the router or provider.
Does a DHCP address prove a device is authorized?
No. DHCP provides network configuration; device identity checks and resource access are handled by separate access-control policy.