Name this pingall.bat replace with the first 3 octs of your domain. This also assumes that you will get "Reply" for a good reply

@echo off

:START

call add.bat

ping 127.0.0.%H%%T%%D% | find "Reply" > nul

if not errorlevel 1 echo %H%%T%%D% >> GoodPing.txt

if %H%%T%%D%==254 goto DONE

goto START

:DONE

Call this add.bat and put in the same directory.

:: ADD.BAT

:: Increments a three digit number

:: Works by comparing each digit

:: H=hundreds, T=tens, D=digits

@echo off

if [%H%]==[] set H=1

if [%T%]==[] set T=0

if [%D%]==[] set D=0

:DIGITS

if %D%==9 goto TENS

if %D%==8 set D=9

if %D%==7 set D=8

if %D%==6 set D=7

if %D%==5 set D=6

if %D%==4 set D=5

if %D%==3 set D=4

if %D%==2 set D=3

if %D%==1 set D=2

if %D%==0 set D=1

goto DONE

:TENS

set D=0

if %T%==9 goto HUNDREDS

if %T%==8 set T=9

if %T%==7 set T=8

if %T%==6 set T=7

if %T%==5 set T=6

if %T%==4 set T=5

if %T%==3 set T=4

if %T%==2 set T=3

if %T%==1 set T=2

if %T%==0 set T=1

goto DONE

:HUNDREDS

set T=0

if %H%==9 set H=0

if %H%==8 set H=9

if %H%==7 set H=8

if %H%==6 set H=7

if %H%==5 set H=6

if %H%==4 set H=5

if %H%==3 set H=4

if %H%==2 set H=3

if %H%==1 set H=2

if %H%==0 set H=1

goto DONE

:DONE

echo %H%%T%%D%

You may strip the HUNDREDS off for the first 89 and then use the full format for all over 100. Play with it and see what you think.