DOS network utilities

There are several important DOS commands which are very useful for troubleshooting network problems.

WINIPCFG - This command is used on Windows 9x systems to display network adapter information such as IP address, subnet mask, default gateway, MAC address, DNS and DHCP settings. You can also release and renew DHCP settings with this Windows graphical user interface. This command was replaced with IPCONFIG in Windows NT/2000/XP.

IPCONFIG - This utility performs the same task as WINIPCFG in Windows NT, 2000 and XP, however it has a command line interface.
Useful switches are:

• Ipconfig/Release - releases your IP from your network adapter back to the DHCP server
• Ipconfig/Renew - requests a new IP address from the DHCP server
• Ipconfig/All - Shows detailed configuration
  

TRACERT - This command allows you to look at the network path a packet takes on its way from one point to another. Using this command you can diagnose which points of a network are causing traffic bottlenecks.
Useful TRACERT switches are:

• Tracert /D - Specify NOT to resolve IP addresses using DNS
• Tracert /H - Max hop count to travel to reach target
  
• Tracert /W - Timeout period in milliseconds for each response
  

PING - The ping command is a very useful command which allows you to test network connectivity with another host.

E.g.

C:\>PING www.pc-technician.net

Useful PING switches include:

• Ping /T - Pings host until user stops the command using Control+c
• Ping /A - Resolves addresses using DNS (This can slow the ping process considerably)
• Ping /I - Specify Time To Live (TTL) , default TTL is 251
• Ping /L - Specify packet size to send, default 32 bytes

NSLOOKUP - This utility is used to query the Domain Name System (DNS) servers directly to check the system is resolving names properly.

E.g.

C:\>NSLOOKUP www.pc-technician.net
Server: adnslookup.net
Address: 62.241.163.200

Non-authoritative answer:
Name: pc-technician.net
Address: 213.232.107.153
Aliases: www.pc-technician.net

Other network related MS-DOS commands can be found on ComputerHope.com.