Using the Netsh.exe utility, and the technique from tip 10130, I have scripted dhcpMAC.bat to return all the MAC address of DHCP clients on my network.

The dhcpMAC.bat batch script requires no parameters. It MUST be run from a DHCP client. To redirect the MAC addresses to a file, use dhcpMAC>FileName.

dhcpMAC.bat contains:

@echo off

setlocal EnableDelayedExpansion

if exist "%TEMP%dhcpMAC.TM1" del /q "%TEMP%dhcpMAC.TM1"

set srv=N

set srvkey=HKLMSYSTEMCurrentControlSetServicesTcpipParameters

for /f "Tokens=3" %%a in ('reg query %srvkey% /V dhcpNameServer^|find /i "dhcpNameServer"') do (

 set srv=\%%a

)

if "%srv%" EQU "N" goto nodhcp

for /f "tokens=1" %%a in ('netsh dhcp server %srv% show scope^|find /i "Active"') do (

 set scope=%%a

 for /f "tokens=3-8 Delims=-" %%b in ('netsh dhcp server %srv% scope !scope! show clients^|find " -D"') do (

  set MAC=%%b-%%c-%%d-%%e-%%f-%%g

  set MAC=!MAC: =!

  @echo !MAC!>>"%TEMP%dhcpMAC.TM1"

 )

 for /f "tokens=3-8 Delims=-" %%b in ('netsh dhcp server %srv% scope !scope! show clientsv5^|find " -D"') do (

  set MAC=%%b-%%c-%%d-%%e-%%f-%%g

  set MAC=!MAC: =!

  @echo !MAC!>>"%TEMP%dhcpMAC.TM1"

 )

)

sort "%TEMP%dhcpMAC.TM1" /O "%TEMP%dhcpMAC.TM2"

del /q "%TEMP%dhcpMAC.TM1"

set /p prev=<"%TEMP%dhcpMAC.TM2"

@echo.%prev%

for /f "Skip=1 Tokens=*" %%a in ('type "%TEMP%dhcpMAC.TM2"') do (

 if "%%a" NEQ "!prev!" @echo.%%a&set prev=%%a

)

del /q "%TEMP%dhcpMAC.TM2"

endlocal

goto :EOF

:nodhcp

@echo ERROR: There is no DHCP server configured for %ComputerName%.

endlocal

Does your 100MB EtherNet TCP/IP network perform poorly?. 10-Nov-97

If your 100MB EtherNet TCP/IP network performs poorly, it could be due to ACK collisions. You can contact your NIC manufacturer to see if there is a way to increase the interframe gap.

The Intel EtherExpress 100B adapters have a registry parameter:

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicese100bxParameters

where x is the number of your interface card. Add Value name Adaptive_ifs as type REG_DWORD and set it to 1. This will enable an adaptive algorithm, while 0 will disabled it. A value of 2 - 200 sets a predefined interframe gap, if you want to measure collisions at 20, 40, 60, ..... and pick one with a low collision rate and good performance.

If you have a different NIC, edit:

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesTcpipParameters

and add Value name TcpWindowSize as type REG_DWORD and set it to 2920 (decimal).

Note: This tip is for 100MB EtherNet TCP/IP networks only. Using this parameter on a 10MB network, or on a WAN or FDDI, or Token Ring, or anything else, will impact performance.

A Windows Installer installation on Terminal Server or Remote Desktop connection reports an error 2755 or error 1305?