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vb.net : How to access the NT Name Cache?
Have you looked at your hosts file? This file can be used to do exactly
what you are asking about. If your program just opened this text file and appended to it, you'd get what you want. [quoted text, click to view] "Michael M." <nospam@mike.com> wrote in message news:%23crnTOSMHHA.600@TK2MSFTNGP02.phx.gbl... > OK. > > So I opended the IPconfig.exe from C:\windows\system32\ > > I see an External sysbol link to a function called DnsGetCacheDataTable() > Sounds like it could be the one! > > Does any one no where to get the C/C++ header for this or an already VB > converted one. > > Its not listed in the Win2k3 SDK > > regards > > Mike. > > "Michael M." <nospam@mike.com> wrote in message > news:%23GJxQJSMHHA.1280@TK2MSFTNGP04.phx.gbl... >> Hi all, >> >> I would like to know how to access the NT/2000/XP/2003 Name cache; what I >> mean by this is: >> >> Open a Command Prompt and.., >> >> C:\> >> C:\>IPCONFIG /DISPLAYDNS >> >> You will see a bunch of cached name records for pretty much all of the >> websites / domains that have been resovled since you booted the computer. >> I would realy like to know what API or function I could access this data >> with so it could speed up my DNS lookups but I have been unable to find >> the API function. >> >> Please help >> >> Regards, >> >> Michael. >> >> >> > >
Very interesting question... there's so little out there!
All I've learned so far is that the DnsGetCacheDataTable() function is in dnsapi.dll, but you've probably already figured that one out. There appears to be good info in the article titled: "Explore the Windows DNS cache" here: http://www.codepieces.net/ , but I guess I'm not literate enough to understand the example. I was thinking I could just figure out where the cache is stored and access it myself, but I've learned it's all in RAM, so no-go on that front. Anyway, good luck! -- Eric [quoted text, click to view] "Michael M." <nospam@mike.com> wrote in message
news:#crnTOSMHHA.600@TK2MSFTNGP02.phx.gbl... > OK. > > So I opended the IPconfig.exe from C:\windows\system32\ > > I see an External sysbol link to a function called DnsGetCacheDataTable() > Sounds like it could be the one! > > Does any one no where to get the C/C++ header for this or an already VB > converted one. > > Its not listed in the Win2k3 SDK > > regards > > Mike. > > "Michael M." <nospam@mike.com> wrote in message > news:%23GJxQJSMHHA.1280@TK2MSFTNGP04.phx.gbl... >> Hi all, >> >> I would like to know how to access the NT/2000/XP/2003 Name cache; what I >> mean by this is: >> >> Open a Command Prompt and.., >> >> C:\> >> C:\>IPCONFIG /DISPLAYDNS >> >> You will see a bunch of cached name records for pretty much all of the >> websites / domains that have been resovled since you booted the computer. >> I would realy like to know what API or function I could access this data >> with so it could speed up my DNS lookups but I have been unable to find >> the API function. >> >> Please help >> >> Regards, >> >> Michael. >> >> >> >
Hey Mike,
I wish I had more info. for you, but I can tell you that typing "ipconfig /?" <---no space bettween / and ? does give you a list of all command line switches. good luck [quoted text, click to view] "Michael M." <nospam@mike.com> wrote in message news:uZeHnfTMHHA.3312@TK2MSFTNGP03.phx.gbl... > Thanks Scott, > > I am aware of the Hosts file, but this is static, only your localhost > 127.0.0.1 record is there by default, it does not get automaticly updated. > > This file is loaded into the name cache you can it's entrys IPconfig / > DisplayDns, but > IPconfig / FlushDns does not remove them (Why are these commands not > listed when you type IPconfig / ? they are not exactly secret ????) > > Win XP does Names likes this I believe > > Host File & LMhost file -> loads into cache -> check cache -> check dns > server <-> wait for lookup > > on a NT / 2Kx domain might append default DNS suffix to the name and check > for that as well. > > Anyway what I want is: > > Lets say the scenario of a internet access / NAT windows server that has a > bunch of connections to webservers. All of thoose webservers has already > been translated to IP addresses, and stored in that name cache and > (depending on Time To Live) will be threre for some time. > > It makes no sense for an application to launch a new thread and lookup > Google.com or Microsoft.com again when it has allready been done and > stored. I would like to read that data into an array or List every 60 > seconds or so, and search that before doing a lookup (I will be doing > reverse lookup so won't be able to rely on NT searching the cache for me) > > I have found a C++ exmple code that has some clues on this, if can convert > it and get it to work I will naturaly post back here. > > The other thing is writing to that file could leave stale records, I would > have to loop through and them update them or Cleint computers would lose > domain resovles on the LANs that the software runs on. > > Thanks for your reply though, I have seen add / popup blocking software > write Dodgy Domains to that file! > > Example > Adverts.SomeDodgyCompany.Com 127.0.0.1 > > or is it the other way round? > > That will not resovle so is quite effective :0) > > Regards > > Mike. > "Scott M." <s-mar@nospam.nospam> wrote in message > news:e50keuSMHHA.3944@TK2MSFTNGP06.phx.gbl... >> Have you looked at your hosts file? This file can be used to do exactly >> what you are asking about. If your program just opened this text file >> and appended to it, you'd get what you want. >> >> >> "Michael M." <nospam@mike.com> wrote in message >> news:%23crnTOSMHHA.600@TK2MSFTNGP02.phx.gbl... >>> OK. >>> >>> So I opended the IPconfig.exe from C:\windows\system32\ >>> >>> I see an External sysbol link to a function called >>> DnsGetCacheDataTable() Sounds like it could be the one! >>> >>> Does any one no where to get the C/C++ header for this or an already VB >>> converted one. >>> >>> Its not listed in the Win2k3 SDK >>> >>> regards >>> >>> Mike. >>> >>> "Michael M." <nospam@mike.com> wrote in message >>> news:%23GJxQJSMHHA.1280@TK2MSFTNGP04.phx.gbl... >>>> Hi all, >>>> >>>> I would like to know how to access the NT/2000/XP/2003 Name cache; what >>>> I mean by this is: >>>> >>>> Open a Command Prompt and.., >>>> >>>> C:\> >>>> C:\>IPCONFIG /DISPLAYDNS >>>> >>>> You will see a bunch of cached name records for pretty much all of the >>>> websites / domains that have been resovled since you booted the >>>> computer. I would realy like to know what API or function I could >>>> access this data with so it could speed up my DNS lookups but I have >>>> been unable to find the API function. >>>> >>>> Please help >>>> >>>> Regards, >>>> >>>> Michael. >>>> >>>> >>>> >>> >>> >> >> > >
Hi all,
I would like to know how to access the NT/2000/XP/2003 Name cache; what I mean by this is: Open a Command Prompt and.., C:\> C:\>IPCONFIG /DISPLAYDNS You will see a bunch of cached name records for pretty much all of the websites / domains that have been resovled since you booted the computer. I would realy like to know what API or function I could access this data with so it could speed up my DNS lookups but I have been unable to find the API function. Please help Regards, Michael.
OK.
So I opended the IPconfig.exe from C:\windows\system32\ I see an External sysbol link to a function called DnsGetCacheDataTable() Sounds like it could be the one! Does any one no where to get the C/C++ header for this or an already VB converted one. Its not listed in the Win2k3 SDK regards Mike. [quoted text, click to view] "Michael M." <nospam@mike.com> wrote in message news:%23GJxQJSMHHA.1280@TK2MSFTNGP04.phx.gbl... > Hi all, > > I would like to know how to access the NT/2000/XP/2003 Name cache; what I > mean by this is: > > Open a Command Prompt and.., > > C:\> > C:\>IPCONFIG /DISPLAYDNS > > You will see a bunch of cached name records for pretty much all of the > websites / domains that have been resovled since you booted the computer. > I would realy like to know what API or function I could access this data > with so it could speed up my DNS lookups but I have been unable to find > the API function. > > Please help > > Regards, > > Michael. > > >
Thanks Scott,
I am aware of the Hosts file, but this is static, only your localhost 127.0.0.1 record is there by default, it does not get automaticly updated. This file is loaded into the name cache you can it's entrys IPconfig / DisplayDns, but IPconfig / FlushDns does not remove them (Why are these commands not listed when you type IPconfig / ? they are not exactly secret ????) Win XP does Names likes this I believe Host File & LMhost file -> loads into cache -> check cache -> check dns server <-> wait for lookup on a NT / 2Kx domain might append default DNS suffix to the name and check for that as well. Anyway what I want is: Lets say the scenario of a internet access / NAT windows server that has a bunch of connections to webservers. All of thoose webservers has already been translated to IP addresses, and stored in that name cache and (depending on Time To Live) will be threre for some time. It makes no sense for an application to launch a new thread and lookup Google.com or Microsoft.com again when it has allready been done and stored. I would like to read that data into an array or List every 60 seconds or so, and search that before doing a lookup (I will be doing reverse lookup so won't be able to rely on NT searching the cache for me) I have found a C++ exmple code that has some clues on this, if can convert it and get it to work I will naturaly post back here. The other thing is writing to that file could leave stale records, I would have to loop through and them update them or Cleint computers would lose domain resovles on the LANs that the software runs on. Thanks for your reply though, I have seen add / popup blocking software write Dodgy Domains to that file! Example Adverts.SomeDodgyCompany.Com 127.0.0.1 or is it the other way round? That will not resovle so is quite effective :0) Regards Mike. [quoted text, click to view] "Scott M." <s-mar@nospam.nospam> wrote in message news:e50keuSMHHA.3944@TK2MSFTNGP06.phx.gbl... > Have you looked at your hosts file? This file can be used to do exactly > what you are asking about. If your program just opened this text file and > appended to it, you'd get what you want. > > > "Michael M." <nospam@mike.com> wrote in message > news:%23crnTOSMHHA.600@TK2MSFTNGP02.phx.gbl... >> OK. >> >> So I opended the IPconfig.exe from C:\windows\system32\ >> >> I see an External sysbol link to a function called DnsGetCacheDataTable() >> Sounds like it could be the one! >> >> Does any one no where to get the C/C++ header for this or an already VB >> converted one. >> >> Its not listed in the Win2k3 SDK >> >> regards >> >> Mike. >> >> "Michael M." <nospam@mike.com> wrote in message >> news:%23GJxQJSMHHA.1280@TK2MSFTNGP04.phx.gbl... >>> Hi all, >>> >>> I would like to know how to access the NT/2000/XP/2003 Name cache; what >>> I mean by this is: >>> >>> Open a Command Prompt and.., >>> >>> C:\> >>> C:\>IPCONFIG /DISPLAYDNS >>> >>> You will see a bunch of cached name records for pretty much all of the >>> websites / domains that have been resovled since you booted the >>> computer. I would realy like to know what API or function I could access >>> this data with so it could speed up my DNS lookups but I have been >>> unable to find the API function. >>> >>> Please help >>> >>> Regards, >>> >>> Michael. >>> >>> >>> >> >> > >
[quoted text, click to view] "Michael M." <nospam@mike.com> wrote in message : Hi all,news:%23GJxQJSMHHA.1280@TK2MSFTNGP04.phx.gbl... : : I would like to know how to access the NT/2000/XP/2003 Name cache; what I : mean by this is: : : Open a Command Prompt and.., : : C:\> : C:\>IPCONFIG /DISPLAYDNS : : You will see a bunch of cached name records for pretty much all of the : websites / domains that have been resovled since you booted the computer. I : would realy like to know what API or function I could access this data with : so it could speed up my DNS lookups but I have been unable to find the API : function. : : Please help : : Regards, : : Michael. This isn't what you're looking for specifically, and it's really an ugly hack, but.... How about running the IPCONFIG command from a shell and piping the output to a file? (IPCONFIG /DISPLAYDNS > [SOME_FOLDER]\displaydns.dat) From there, you could open the file, parse the contents then delete it. That would do as an interim solution. Ralf -- -- ---------------------------------------------------------- * ^~^ ^~^ * * _ {~ ~} {~ ~} _ * * /_``>*< >*<''_\ * * (\--_)++) (++(_--/) * ---------------------------------------------------------- There are no advanced students in Aikido - there are only competent beginners. There are no advanced techniques - only the correct application of basic principles.
That's what I was suggesting, but instead of "some file", I suggested using
the hosts file, since it is consulted automatically. [quoted text, click to view] "_AnonCoward" <abc@xyz.com> wrote in message news:459fd4ec$0$8987$4c368faf@roadrunner.com... > > "Michael M." <nospam@mike.com> wrote in message > news:%23GJxQJSMHHA.1280@TK2MSFTNGP04.phx.gbl... > : Hi all, > : > : I would like to know how to access the NT/2000/XP/2003 Name cache; > what I > : mean by this is: > : > : Open a Command Prompt and.., > : > : C:\> > : C:\>IPCONFIG /DISPLAYDNS > : > : You will see a bunch of cached name records for pretty much all of > the > : websites / domains that have been resovled since you booted the > computer. I > : would realy like to know what API or function I could access this > data with > : so it could speed up my DNS lookups but I have been unable to find > the API > : function. > : > : Please help > : > : Regards, > : > : Michael. > > > This isn't what you're looking for specifically, and it's really an > ugly hack, but.... > > How about running the IPCONFIG command from a shell and piping the > output to a file? (IPCONFIG /DISPLAYDNS > > [SOME_FOLDER]\displaydns.dat) > > From there, you could open the file, parse the contents then delete > it. That would do as an interim solution. > > Ralf > -- > -- > ---------------------------------------------------------- > * ^~^ ^~^ * > * _ {~ ~} {~ ~} _ * > * /_``>*< >*<''_\ * > * (\--_)++) (++(_--/) * > ---------------------------------------------------------- > There are no advanced students in Aikido - there are only > competent beginners. There are no advanced techniques - > only the correct application of basic principles. > >
Ok I have converted the C++ sample and I have it working now, but I have a
question I am new to VB.net have been only programming on and off for the last two months. using the interop marshal class I need to retrieve a string from a pointer the string is passed from the DnsGetCacheDataTable() so it is a C++ string, all I have is the start memory address of a string; how do I determine the length of the string so I don't hit the tried to read protected memory error? Right now I am just reading 128 bytes from the start address of the string pointer it seems to work about 95 out of 100 which is wierd. Eric <eric@ejproductions.com> posted me this which had a link to C++ example which I converted. <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< Very interesting question... there's so little out there! All I've learned so far is that the DnsGetCacheDataTable() function is in dnsapi.dll, but you've probably already figured that one out. There appears to be good info in the article titled: "Explore the Windows DNS cache" here: http://www.codepieces.net/ , but I guess I'm not literate enough to understand the example. I was thinking I could just figure out where the cache is stored and access it myself, but I've learned it's all in RAM, so no-go on that front. Anyway, good luck! [quoted text, click to view] >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Ps if anyone is intrested I can post my VB.Net port of this function. Regards, Michael. [quoted text, click to view] "Michael M." <nospam@mike.com> wrote in message news:%23crnTOSMHHA.600@TK2MSFTNGP02.phx.gbl... > OK. > > So I opended the IPconfig.exe from C:\windows\system32\ > > I see an External sysbol link to a function called DnsGetCacheDataTable() > Sounds like it could be the one! > > Does any one no where to get the C/C++ header for this or an already VB > converted one. > > Its not listed in the Win2k3 SDK > > regards > > Mike. > > "Michael M." <nospam@mike.com> wrote in message > news:%23GJxQJSMHHA.1280@TK2MSFTNGP04.phx.gbl... >> Hi all, >> >> I would like to know how to access the NT/2000/XP/2003 Name cache; what I >> mean by this is: >> >> Open a Command Prompt and.., >> >> C:\> >> C:\>IPCONFIG /DISPLAYDNS >> >> You will see a bunch of cached name records for pretty much all of the >> websites / domains that have been resovled since you booted the computer. >> I would realy like to know what API or function I could access this data >> with so it could speed up my DNS lookups but I have been unable to find >> the API function. >> >> Please help >> >> Regards, >> >> Michael. >> >> >> > >
What an idiot.
I did not check the overload options of Marshal.PtrToStringAuto the second option does not require a length guess it finds the first null char or something then returns the left all chars to the left of that? Michael. [quoted text, click to view] "Michael M." <nospam@mike.com> wrote in message news:%23x4kfFqMHHA.2140@TK2MSFTNGP03.phx.gbl... > Ok I have converted the C++ sample and I have it working now, but I have a > question > > I am new to VB.net have been only programming on and off for the last two > months. > > using the interop marshal class I need to retrieve a string from a pointer > the string is passed from the > > DnsGetCacheDataTable() so it is a C++ string, all I have is the start > memory address of a string; how do I determine the length of the string so > I don't hit the tried to read protected memory error? > > Right now I am just reading 128 bytes from the start address of the string > pointer it seems to work about 95 out of 100 which is wierd. > > Eric <eric@ejproductions.com> posted me this which had a link to C++ > example which I converted. > > <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< > Very interesting question... there's so little out there! > > All I've learned so far is that the DnsGetCacheDataTable() function is in > dnsapi.dll, but you've probably already figured that one out. There > appears > to be good info in the article titled: "Explore the Windows DNS cache" > here: > http://www.codepieces.net/ , but I guess I'm not literate enough to > understand the example. > > I was thinking I could just figure out where the cache is stored and > access > it myself, but I've learned it's all in RAM, so no-go on that front. > > Anyway, good luck! >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> > > > Ps if anyone is intrested I can post my VB.Net port of this function. > > Regards, > > Michael. > > > > "Michael M." <nospam@mike.com> wrote in message > news:%23crnTOSMHHA.600@TK2MSFTNGP02.phx.gbl... >> OK. >> >> So I opended the IPconfig.exe from C:\windows\system32\ >> >> I see an External sysbol link to a function called DnsGetCacheDataTable() >> Sounds like it could be the one! >> >> Does any one no where to get the C/C++ header for this or an already VB >> converted one. >> >> Its not listed in the Win2k3 SDK >> >> regards >> >> Mike. >> >> "Michael M." <nospam@mike.com> wrote in message >> news:%23GJxQJSMHHA.1280@TK2MSFTNGP04.phx.gbl... >>> Hi all, >>> >>> I would like to know how to access the NT/2000/XP/2003 Name cache; what >>> I mean by this is: >>> >>> Open a Command Prompt and.., >>> >>> C:\> >>> C:\>IPCONFIG /DISPLAYDNS >>> >>> You will see a bunch of cached name records for pretty much all of the >>> websites / domains that have been resovled since you booted the >>> computer. I would realy like to know what API or function I could access >>> this data with so it could speed up my DNS lookups but I have been >>> unable to find the API function. >>> >>> Please help >>> >>> Regards, >>> >>> Michael. >>> >>> >>> >> >> > >
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