I have the problem that some DNS entries provide aliases and addionanal IP6 addresses, while others do provide several IP4 addresses and those may change from answer to answer.
Asking DNS servers for IP4 only, does result in timeout for the script and does not solve the changing (loadbalanced) IP4 addresses.
For test you may use these domains for example:
- www.stackoverflow.com
- www.heise.de
- www.dell.de
These are nice examples because, first domain does provides an alias after the IP address which I could filter by find easily. But second does provide an IP6 additionally which should get filtered too and last not least Dell provides different addresses with almost each returned answer.
This is the partial piece of my code:
set TESTDNS=www.dell.de
set TESTIP=143.166.83.190
FOR /F "skip=1 delims=: tokens=2 usebackq" %%j in (`nslookup %TESTDNS% 2^>NUL 1^| find "Address"`) do set XIP=%%j
set XIP=%XIP: =%
do more like compare etc. ....
if NOT %TESTIP%==%XIP% ( ... )
Could someone show me how to filter IP6 adresses out (maybe with findstr [0-9] - but the more how to check if my last known IP address is in the provided new answer, because if so i do not need to change it in my configs.
SOLUTION:
From MC ND's answer i used his function as straight code (for use in another Loop), without use of call. The only thing i really changed exept of var names is to add strip whitespaces from the IP which does otherwise break the function as "1.2.3.4" =! "1.2.3.4 "
D)
for x do ( ...
REM go get dns resolution and set vars to test and compare
set "XIP="
for /f "skip=1 tokens=*" %%a in ('nslookup "%TESTDNS%" 2^>nul ^| findstr /i /r /c:"address[e]*[s]*:.*\." /c:"address[ ]*=.*\." /c:"^[ ][ ]*[0-9].*\." ') do (
rem get nslookup output
set "_line=%%a"
rem remove spaces
set "_line=!_line: =!"
rem parse line
for /f "tokens=1,* delims=:=" %%b in ("!_line!") do (
rem retrieve the correct section of the line
if "%%c"=="" (
set "XTIPX=%%b"
) else (
set "XTIPX=%%c"
)
REM trim whitespaces from var
set XTIPX=!XTIPX: =!
rem test address match to old address
if "!XTIPX!"=="%TESTIP%" (
set "XIP=!XTIPX!"
goto endRESTESTDNS
)
rem if no match, the first address found is saved
if not defined XIP set "XIP=!XTIPX!"
)
)
:endRESTESTDNS
do more like compare etc. ....
experimental code:
@ECHO OFF
SETLOCAL ENABLEEXTENSIONS ENABLEDELAYEDEXPANSION
REM ++++++++++++++++++++++++++++ BLAT EMAIL CONFIG ++++++++++++++++++++++++++++++++++++
set eMailTO=someone@somedomain.somewhere
set eMailFROM=dnstestscript
set server=0.0.0.0
REM you have to install blat of course, here "echo blat ..." is used where it would be
REM useful to send an email on interesting items, but it is also sent to shell and log
REM +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
REM ++++++++++++++++++++++++++++ SCRIPT CONFIG ++++++++++++++++++++++++++++++++++++++++
set "XScriptnamE=%~n0"
set "XSCRIPTDIR=%~dp0"
set "LOGDIR=%XSCRIPTDIR%\%XScriptnamE%"
if not exist "%LOGDIR%" mkdir "%LOGDIR%"
set "LOG=%LOGDIR%\%XScriptnamE%.log"
REM make errorlooging expand
set "XLOGX=xpipex && type xpipex && type xpipex >> %LOG%"
REM or make individual run logs
REM set "LOG=%LOGDIR%\%XScriptnamE%-%STAMP%.log"
REM not global vars come here
set "DNSTESTFILE=%XSCRIPTDIR%\dnstests.txt"
REM +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
REM do never set something here at errorlog plz otherwise compare of happened errors wont work
set errorlog=
pushd=%XSCRIPTDIR%
REM ++++++++++++++++++++++++++++ MAKE DATE ++++++++++++++++++++++++++++++++++++++++++++
for /F "usebackq tokens=1,2 delims==" %%i in (`wmic os get LocalDateTime /VALUE 2^>NUL`) do if '.%%i.'=='.LocalDateTime.' set ldt=%%j
REM make timestamp (date reverse)
set STAMP=%ldt:~0,4%-%ldt:~4,2%-%ldt:~6,2%--%ldt:~8,2%-%ldt:~10,2%--%ldt:~12,2%-%ldt:~15,3%
REM +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
echo ================================================== >> %LOG%
echo Script run at %STAMP% >> %LOG%
REM +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
REM ++++++++++++++++++++++++++++ START ++++++++++++++++++++++++++++++++++++++++++++++++
REM if the script is run in cmd we see enoght information to follow actions but they are written to a log file too for sheduled use
REM ++++++++++++ make a loop for each line in file ++++++++++++++++++++++++++++++++++++
REM read them in different vars to call processing
REM check for test file
if NOT exist "%DNSTESTFILE%" (
set errorlog=%errorlog% : error dns file not exist :
echo blat error dnsfile
echo error dnsfile not exist >> %log%
)
REM read test file
set Counter=1
for /f %%s in (%DNSTESTFILE%) do (
set "Line_!Counter!=%%s"
set /a Counter+=1
)
set /a NumLines=Counter - 1
REM make a backup of old test file before nulling it, by files date you see last ip change
copy /y %DNSTESTFILE% %DNSTESTFILE%.bak 2>&1 > %XLOGX%
REM as i found no way to rewrite the specific line i choose to read out all lines in vars, now we nul the file and rewrite lines later
type NUL > %DNSTESTFILE%
REM now use vars to call processing
for /l %%r in (1,1,%NumLines%) do (
set "q=!Line_%%r!"
echo. >> %log%
echo.
call :check !q!
)
REM did all go well or what did we miss?
if NOT "%errorlog%."=="." (
echo.
echo blat summary %errorlog%!
echo. >> %LOG%
echo %errorlog%! >> %LOG%
)
REM ++++++++++++++++++++++++++++ END +++++++++++++++++++++++++++++++++++++++++++++++++++
REM next line tells us script did run through code while one may want to save this lines
echo ==================script finished================= >> %log%
del xpipex
break
goto :eof
REM ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
REM +++++++++++++++++++++++++++++ PROCESSING +++++++++++++++++++++++++++++++++++++++++++
:check
REM trim whitespace from beginning and end of line
for /f "tokens=* delims=" %%z in ("!q!") do (
set "line=!q!"
REM test if line is valid dns AND ip address syntax BUT only informational because of limited regular expression support of findstr and "1234.2.3.4" is also accepted as well formatted address
echo !line! | findstr /i /r "^[a-z0-9-]*\.[a-z0-9-]*\.[a-z0-9-]*=[0-9]*\.[0-9]*\.[0-9]*\.[0-9]*" >NUL || (
echo blat error in dns test line syntax with: !line!
set errorlog=%errorlog% : error in dns test line syntax with: !line! :
)
REM test that trimmed line matches at least once "^char=number$" and set vars for test
echo !line! | findstr /i "^[a-z]*=[0-9]*$" >NUL && do (
for /f "tokens=1,2 delims==" %%x in ("!q!") do set TESTDNS=%%~x&set TESTIP=%%~y
)
REM trim whitespace from beginning and end of var
set TESTDNS=%TESTDNS: =%
set TESTIP=%TESTIP: =%
echo testing %TESTDNS% to %TESTIP%
echo checking %TESTDNS%: >> %LOG%
REM go get dns resolution and set vars to test and compare
echo. ############################
nslookup %TESTDNS%
echo. ############################
set "XIP="
for /f "skip=1 tokens=*" %%a in ('nslookup "%TESTDNS%" 2^>nul ^| findstr /i /r /c:"address[e]*[s]*:.*\." /c:"address[ ]*=.*\." /c:"^[ ][ ]*[0-9].*\." ') do (
rem get nslookup output
echo testing %TESTDNS% to %TESTIP% -1
set "_line=%%a"
rem remove spaces
set "_line=!_line: =!"
rem parse line
for /f "tokens=1,* delims=:=" %%b in ("!_line!") do (
rem retrieve the correct section of the line
echo testing %TESTDNS% to %TESTIP% -2
if "%%c"=="" (
set "XTIPX=%%b"
) else (
set "XTIPX=%%c"
)
echo testing %TESTDNS% to %TESTIP% -3 "!XTIPX!"
echo !XTIPX! > 1.txt
echo %TESTIP% > 2.txt
REM trim whitespace from beginning and end of var
rem set XTIPX=!XTIPX: =!
rem test address match to old address
if "!XTIPX!"=="%TESTIP%" (
echo testing %TESTDNS% to %TESTIP% -4 !XTIPX!
set "XIP=!XTIPX!"
goto endRESTESTDNS
)
rem if no match, the first address found is saved
if not defined XIP set "XIP=!XTIPX!"
echo testing %TESTDNS% to %TESTIP% -5
)
)
:endRESTESTDNS
REM if dsn did change
if NOT %XIP%==%TESTIP% (
echo %TESTDNS% now is %XIP%
REM inform us
echo blat dns for given %TESTDNS% did change from %TESTIP% TO %XIP%!
echo dns did change from %TESTIP% TO %XIP%! >> %LOG%
REM fill a log-var to report allover later in mail for example
set errorlog=%errorlog% : dns for given %TESTDNS% dis change from %TESTIP% TO %XIP%! :
REM do not forget to write back
echo %TESTDNS%=%XIP% >> %DNSTESTFILE%
)
if %XIP%==%TESTIP% (
REM if dns did not change
echo ip did not change
REM we should not forget to write back the route to our testfile
echo %TESTDNS%=%XIP% >> %DNSTESTFILE%
echo - OK >> %LOG%
)
)
:EOF