Windows NT 4 includes numerous command-line utilities that
can help you troubleshoot network problems. However, while you’re more than
likely familiar with most of these tools, running into unexpected network
issues can sometimes cause your mind to go blank. Here’s a quick list of five
Windows NT utilities that every administrator should keep in his or her IT
toolkit.

IPCONFIG

IPCONFIG is a basic utility for diagnosing problems with
TCP/IP, and it also displays some TCP/IP settings, including IP address, subnet
mask, and default gateway. Using the /all switch with IPCONFIG displays
additional information, such as DNS servers, physical MAC address, DHCP
settings, and more. You can also use the /release and /renew switches to
release or renew the IP address lease from the DHCP server.

NBTSTAT

NBTSTAT displays protocol statistics and current TCP/IP
connections using NetBIOS over TCP/IP (NBT). You can also use NBTSTAT to
display registered NetBIOS names.

NETSTAT

NETSTAT displays even more TCP/IP statistics and connections.
If you want to know which ports are open on your machine, enter netstat -a,
and the system will return a list of all open protocols and remote connections
that are using these ports. You can also display the routing table with netstat
-r, or you can view some
TCP/IP statistics using netstat -s.

NSLOOKUP

NSLOOKUP is useful if you have problems with DNS servers or
you need to manually query DNS servers for host records. Advanced users can
also list all records in DNS domains.

PING

PING is the most basic TCP/IP troubleshooting tool.
Administrators use it to make sure they’ve installed the TCP/IP stack correctly
and that the network connection works. PING uses ICMP Echo requests and replies,
which firewalls can block on some networks. This is why PING times out even
when the connection with a remote machine works.