Practical TCP/IP and Ethernet Networking- P38 ppsx

This is used for obtaining protocol statistics and current active connections utilizing TCP/IP.. Displays protocol statistics and current TCP/IP network connections.. -p proto Shows conn

This is used for obtaining protocol statistics and current active connections utilizing TCP/IP Nowadays there are many Windows-based utilities that can do much more; yet in

an emergency netstat is certainly better than nothing at all Here follows the netstat options

C:\WINDOWS.000>netstat /?

Displays protocol statistics and current TCP/IP network connections

NETSTAT [-a] [-e] [-n] [-s] [-p proto] [-r] [interval]

-a Displays all connections and listening ports

-e Displays Ethernet statistics This may be combined with the

-s option

-p proto Shows connections for the protocol specified by proto; proto

may be TCP or UDP If used with the -s option to display per-protocol statistics, proto may be TCP, UDP, or IP

shown for TCP, UDP and IP; the -p option may be used to specify a subset of the default

interval Re-displays selected statistics, pausing interval seconds

between each display

Press CTRL+C to stop re-displaying statistics If omitted, netstat will print the current configuration information once C:\WINDOWS.000>

In response to the netstat -e command the following packet and protocol statistics are displayed This is a summary of events on the network since the last re-boot

C:\WINDOWS.000>netstat -e

Interface Statistics

C:\WINDOWS.000>

This provides protocol statistics and current TCP/IP connections using NBT (NetBIOS over TCP/IP) This is relevant with Windows 95/98 etc, which uses NetBIOS for the upper layers of the OSI model

C:\WINDOWS.000>nbtstat /?

Displays protocol statistics and current TCP/IP connections using NBT (NetBIOS over TCP/IP)

NBTSTAT [-a RemoteName] [-A IP address] [-c] [-n] [-r]

[-R] [-s] [S] [interval] ]

its name

-A (Adapter status) Lists the remote machine’s name table given

its IP address

addresses

addresses

addresses to host names via the hosts file

IP address Dotted decimal representation of the IP address

Interval Re-displays selected statistics, pausing interval seconds

between each display Press Ctrl+C to stop re-displaying statistics

C:\WINDOWS.000>

This shows the entire TCP/IP configuration present in a host It also has the additional versatility of interfacing with a DHCP server to renew a leased IP address

Ipconfig will return, amongst other things, the host’s IP address, its subnet mask and default gateway

C:\WINDOWS.000>ipconfig /?

Windows 98 IP Configuration

Command line options:

/All - Display detailed information

/Batch [file] - Write to file or /WINIPCFG.OUT

/release_all - Release all adapters

C:\WINDOWS.000>

An options often used is ‘ipconfig /all’ In the case of a multi-homed host, i.e one with more than one network interface card (including dial-up modem) ‘ipconfig /all’ will display the details of each card

Note that ipconfig will list the generic name of the adapter Therefore, a 3010 3Com US Robotics 56K modem is simply listed as a PPP adapter, while a Linksys Ethernet 10BaseT/10Base2 Combo PCMCIA card is listed as a generic Novell 2000 adapter, which it emulates

C:\WINDOWS.000>ipconfig /all

Windows 98 IP Configuration

Host Name : COMPUTER100

DNS Servers :

Node Type : Broadcast

NetBIOS Scope ID :

IP Routing Enabled : No

WINS Proxy Enabled : No

NetBIOS Resolution Uses DNS : No

0 Ethernet adapter :

Description : PPP Adapter

Physical Address : 44-45-53-54-00-00

DHCP Enabled : Yes

IP Address : 0.0.0.0

Subnet Mask : 0.0.0.0

Default Gateway :

DHCP Server : 255.255.255.255

Primary WINS Server :

Secondary WINS Server :

Lease Obtained :

Lease Expires :

1 Ethernet adapter :

Description : Novell 2000 Adapter

Physical Address : 00-E0-98-71-57-AF

DHCP Enabled : No

IP Address : 207.194.66.100

Subnet Mask : 255.255.255.224

Default Gateway :

Primary WINS Server :

Secondary WINS Server :

Lease Obtained :

Lease Expires :

C:\WINDOWS.000>

Winipcfg (Windows IP Configuration) provides the same information as ‘ipconfig /all’, but in a Windows format Like ipconfig, it is capable to force a DHCP server into releasing and reissuing leased IP addresses

Figure 9.2

Windows IP configuration

It can be invoked from the DOS prompt, or from the Windows ‘run’ command Click the more details tab for an expanded view

Figure 9.3

Winipcfg display (courtesy of Microsoft Corporation)

This is often used to trace failures along a TCP/IP communications path The spelling of

the command varies slightly For UNIX it is traceroute, for Windows it is tracert

The following figure shows the tracert options

C:\WINDOWS.000>tracert

Usage: tracert [-d] [-h maximum_hops] [-j host-list] [-w timeout] target_name

Options:

-h maximum_hops Maximum number of hops to search for target

-j host-list Loose source route along host-list

-w timeout Wait timeout milliseconds for each reply

C:\WINDOWS.000>

Here follows a route trace from Perth, Australia, to a server in the USA

C:\WINDOWS.000>tracert www.idc-online.com

Tracing route to www.idc-online.com [216.55.154.228] over a maximum of 30 hops:

1 169ms 160ms 174ms slip202-135-15-3-0.sy.au.ibm.net [202.135.15.30]

2 213ms 297ms 296ms 152.158.248.250

3 624ms 589ms 533ms sfra1sr1-2-0-0-5.ca.us.prserv.net [165.87.225.46]

4 545ms 535ms 628ms sfra1sr2-101-0.ca.us.prserv.net [165.87.33.185]

5 564ms 562ms 573ms 165.87.160.193

6 558ms 564ms 573ms 114.ATM3-0.XR1.SFO1.ALTER.NET

9 504ms 534ms 511ms 297.ATM7-0.XR1.LAX2.ALTER.NET

10 500ms 478ms 491ms 195.ATM9-0-0.GW2.SDG1.ALTER.NET

11 491ms 564ms 584ms anet-gw.customer.ALTER.NET [157.130.224.154]

12 575ms 554ms 613ms www.idc-online.com [216.55.154.228]

Trace complete

C:\WINDOWS.000>

As is often the case, the DOS approach is not the user-friendliest option Notice the result when the same trace is done with TJPingPro The same TCP/IP protocols viz ARP and ICMP are still used, but now they are accessed through a third-party application program (TJPingPro) which accesses the TCP/IP stack through a WinSock interface

Figure 9.4

TJPingPro trace (courtesy of Top Jimmy Software)

The most comprehensive tracing is, however, done via application programs such as Neotrace The following figures give some of the results of a trace to the same location used for the previous two examples

Figure 9.5

NeoTrace display (courtesy NeoWorx Inc)