TCP/IP UTILITIES

Using the Address Resolution Protocol

Translates TCP/IP addresses into MAC addresses using brodcast. Machine needing a physical address broadcasts "hey, who is address.....", the machine owning the address responds with its MAC address. The address is then added to the ARP table.

The Windows ARP Table

TCP/IP address to MAC address translation table.
Stored in memory.
Includes a TTL (time to live) that gives an expiration for the address.
Dynamic...built as the machines broadcast and respond.
Static...built manually using the ARP utility.

The ARP Utility

arp -a arp - s IP MAC arp -d IP

Displays the IP address assigned to the physical address. Allows you to manually assign an IP to a MAC address. Removes the entry form the ARP table

Using netstat

Allows you to see the incoming and outgoing TCP/IP connections. You can also see packet statistics. Using Netystat with the switch plus a time following the switch allows netstat to run every few seconds. Example: netstat -e 5 runs netstat every 5 seconds.

The -a Switch

Displays all TCP/IP connections and UDP protocol connections. Remember that UDP protocols are broadcast so they will not have a foreign address or State.

The -e Switch

Displays a summary of all the packets that have been send over the NIC.

Unicast Packets - Packets addressed either to or from this computer.
Non-unicast Packets - Number odf packets received that are not directly from or to another PC such as a broadcast packet.
Discards - Ususable packets.
Errors - Number of errors that occurred during transmission or reception.
Unknown Protocols - Number of received packerts that the Windows system could not interpret.

The -r Switch

Displays the current routing table.

The -s Switch

Displays a pile o' statistics. Most you can figure out, else goto www.microsoft.com/support/.

The -n Switch

Modifier for the other switches.
Causes netstat to display addresses rather than names.

The -p Switch

Modifier for other switches.
Used to specify which protocols you wish to display when you use the -s switch.

The nbstat Utility

Used to track NetBIOS names over TCP/IP
Only available on Win 95/98/NT computers (NetBIOS is a Micro$oft product)

The -a switch

Displays the remote machine's NetBIOS name table.
Contains: machine name, ID number, Unique host or a workgroup, Status of the name.

The -A Switch

Same as the -a switch except the machine is identified with the IP address. The diplay of information is the same.

The -c Switch

Displays the local NetBIOS name cache (not a distant workstation).
Display is similar to -a except Life is given which indicates how long this entry will live in cache.

The -n switch

Displays the local NetBIOS name table (not a distant workstation).
Display is the same as the -a switch except it is for the local machine.

The -r Switch

Displays information about the number of names that have been resolved to TCP/IP addresses.

The -R Switch

Reloads the NetBIOS name cache with the contents of the LMHOSTS file.

The -S switch

Lists the NetBIOS session table which listas all session incoming and outgoing to and from wherever the command was issued.
Includes information on the amount of data that has been send in or out.

The -s Switch

Similar to the -s switch except that it tries to resolve the host IP addresses of the remote computer into host names.

The File Transfer Protocol (FTP) Utility

Cross-platform protocol for transfering files between servers.
FTP client
FTP from the command prompt

The Ping Utility

Used to determine if you can reach a host or if a host is responding.

ping (host name or IP address)

Switches:

-? - displayes the switchea and options
-a - Resolves the pinged address to a host name
-n # - pings the host a set number of times
-t - Pings continually until you push Ctrl C.
-r - #records the route taken to ping the host up to 9 hops.

The winipcfg and ipconfig Utilities

Try 'em! You'll like 'em!

Winipcfg give Useful information about the IP adderss, subnet mask and default gateway. Allows you to release and renew DHCP leases.

Ipconfig is similar to winipcfg except it is designed to be compatible with many operating systems. There are 4 switches:

/? - Describes the switches and options.
/All - Displays all TCP/IP configuration information.
/Release - Releases all TCP/IP configuration information received from the DHCP server.
/Renew - Releases, then renews all TCP/IP configuration information from the DHCP server.

The tracert Utility

Shows the route that a packet takes between your computer and a distant host. To use tracert you simply type tracert and the ipaddress or DNS name of the distant host.

The Telnet Utility

Terminal Emulation for Networks. Originally for Unix to Unix remote login and communication.

The nslookup Utility

Not available with Win 95/98.
nslookup allows you to test the DNS server to see which ip addresses resolve to which DNS names.

Type=mx Domain=<domain name> Retry=X

Returns the responsible e-mail server for that domain. Sets the current domain name to <domain name> Specifies the number of retries (the number of seconds is specified by X)

 

Vocabulary

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