I am facing problem where after changing host name my application is failing. In investigation i found that Dns.GetHostName() is still returning old host name .
I am trying to get info on source of host name for function Dns.GetHostName().
Thanks a lot
Dns.GetHostName queries your DNS servers registered in your IP settings for your name (that's why it can return socket exception). DNS info is cached. You can do ipconfig /flushdns to clear it.
You can also get the netbios machine name from Environment.MachineName which is the static machine name from the registry. Note that netbios machine names are limited to 15 chars while DNS names are not.
If you have just changed your MachineName, the new name doesn't take effect until the next time you restart your computer. I'm not 100% sure if this function works the Same way as Environment.Machinename (which is definately not updated until next restart).
Related
I want to connect to a ActiveDirectory using c#.
I need to be able to connect to an DC which I can only resolve using an IP Address (which I have).
The next step is to find a computer in the DC address leases to resolve the IP address of a computername entered by a user.
Can someone give me a heads up?
I should be using
DirectoryEntry directoryEntry = new DirectoryEntry("LDAP://DC-IpAddress");
directoryEntry.Path = "LDAP://(What should I enter here for "Address Leases"?);
then I need a returned value which gives me the IP-Address of target Computer.
Hope you folks can help me out a bit.
FYI: The DHCP Server is installed on the target DC. just in case ;)
in this link VB project which is contains in the forth section a method that Listing all computers in the Active Directory .. may it helpful for you
http://www.codeproject.com/Articles/19689/Working-with-Active-Directory-in-VB-NET
I was working on Retrieving IP address and client machine name for few days on the internet (not on the local network)
so I found some ways for getting IP-address , but I couldn't find a way for getting client machine name or gathering some info about my web site users ?
I know there are many duplicate threads about this issue out there , but many of them are old or do n't work.
the below server side codes return SERVER NAME Not client computer name !
string UserHost_ComputerName4 = Dns.GetHostName();//Server Name
string UserHost_ComputerName5 = Environment.MachineName;//Server Name
and the below line have error on user-side , but it works on server-side page running :
string UserHost_ComputerName3 = Dns.GetHostEntry(Request.ServerVariables["REMOTE_ADDR"]).HostName.ToString();//Has Error
Would you lead me to a possible and workable ways (JavaScript or jQuery or server side) for getting client (users who are visiting my web site) machine name?
Try this:
string PCName = Dns.GetHostEntry(Request.ServerVariables["REMOTE_ADDR"]).HostName;
But if you want Name of Host PC
string HostPCName = Dns.GetHostName();
As far as I remember, in order to get:
Request.ServerVariables["REMOTE_ADDR"]
Request.ServerVariables["REMOTE_HOST"]
Request.ServerVariables["REMOTE_USER"]
you have to enable Reverse DNS Lookup for you IIS.
p.s.
atm I'm not able to test it myself, so I'm not quite sure if this will solve ur problem
Not entirely sure on all the ways you can do this, but it would be possible through ActiveX, which could be a problem as that only works in some browsers. I don't believe there is a way you can do it with pure javascript, and it's not possible serverside as the server does not get access to such details of it's connected clients.
I have 4 servers participating in load balancing environment. The same ASP.NET application is being hosted in each server.
I would like to get the DNS Name regardless of the underlying server.
Which one of the followings will give the correct answer?
Request.Url.Host
Environment.MachineName
System.Net.Dns.GetHostName()
Thanks for your suggestion!
You could try Request.Url.GetLeftPart(UriPartial.Authority). So for example if the request url is http://www.contoso.com/index.htm?date=today this will return http://www.contoso.com.
The first. It actually is the ONLY one that is even vaguely relevant.
Environment.MachineName may be whatever you want - noone says that has to be exposed via DNS. Espeically in a hosting environment.
System.Net.Dns.GetHostName - will return the host name of the machine, no idea how.
Anyhjoe, both my not be what is used to access the machine. THis is pretty much the Url.Host part only, as this came throug hthe request.
I am trying to create scripts/services that allow for waking PCs in a windows domain via WOL. Now i want to give the user the option to select an AD container as a starting point for the waking of PCs contained within. My initial thought is using DHCP as a repository to query for MAC addresses given the hostnames (which i can easily enough pull from AD given the container).
Is there a way to programmatically query the DHCP service/server, passing hostnames and recover the associated MAC addresses?
Or, is there a better/easier way to solve my problem?
This is a little bit wacky it seems that there's no way to query the DHCP server programmatically. Thanks cottsak for asking the question. I understand that the DHCP protocol doesn't have such a query, but I thought mayb the executable from Microsoft might have some way you can address it from the command line. I haven't heard anybody anywhere say that there is no such case, but it must be so.
WHOA, wait a minute... I think I found what we're looking for: NETSH. cf:
http://social.technet.microsoft.com/Forums/en/ITCG/thread/afb4be16-09bd-4260-b515-8323d85d4ccb
Where it says if you open a command prompt on the DHCP server you can run this command:
netsh dhcp server scope 192.168.1.0 show clients
and get a report such as this:
10.10.98.53 - 255.255.255.0 -00-0c-29-02-a4-09 - NEVER EXPIRES -D
10.10.98.54 - 255.255.255.0 - 00-22-19-10-29-75 -1/21/2012 8:39:25 AM -D
Yippeee! Thanks for the thread!! If it wasn't for this one, I enver would have narrowed my search to technet adn found that one.
Try dhcpexim.exe from microsoft.
or, if you prefer using pure C. DhcpEnumSubnetClientsV4
No problem; because all of the machines are in your domain you can put together a VBScript that will get the MACAddress(es) from the local machine and store it as an attribute of the computer object in Active Directory.
Here's a quick hack on how to do that (save this as a .vbs-file):
Option Explicit
Const ADS_PROPERTY_UPDATE = 2
Const COMPUTERLOCATION = "ou=Member Servers,dc=yourdomain,dc=com"
Const ATTRIBUTETOUSE = "otherTelephone"
Dim wshNetwork, strComputerName
Set wshNetwork = WScript.CreateObject("WScript.Network")
strComputerName = wshNetwork.ComputerName
Dim objWMIService, colNetCards, objComputer, objNetCard
Set objWMIService = GetObject("winmgmts:\\" & strComputerName & "\root\cimv2")
Set colNetCards = objWMIService.ExecQuery("Select * From Win32_NetworkAdapterConfiguration Where IPEnabled = True")
Set objComputer = GetObject("LDAP://cn=" & strComputerName & "," & COMPUTERLOCATION)
For Each objNetCard in colNetCards
objComputer.PutEx ADS_PROPERTY_APPEND, ATTRIBUTETOUSE, Array(objNetCard.MACAddress)
objComputer.SetInfo
Next
Because your clients aren't all in the "Member Servers" OU above you'll need to modify the above script to include a directory search for the strComputerName do get the COMPUTERLOCATION.
When you have a working script, ask your domain administrator to put the script as a start-up script targetting the computers you need to monitor; that way it'll execute whenever a computer boots up. You can also run the script as a scheduled task to get your data from any clients that haven't rebooted or use psexec or some other way you can think of to get the data immediately. Or you can rewrite the script entirely to remote connect to all of your machines and get the data that way (which might not be possible due to local firewalls). Or you could write a small .NET console application which does the same thing, it's up to you...
Also, although there is a networkAddress-attribute defined for computer objects; by default the computer object itself does not have access to write to this property. Because start up-scripts run in the context of the SYSTEM account on the particular machine the easiest thing is to use an attribute that the computer object (SELF) has write access to. The otherTelephone-attribute is multivalued and part of the Personal-Information Property Set which all computer objects has write access to by default. If you want to use the networkAddress-attribute you need to set explicit write access to that attribute for all of your computers.
Also you need to bear in mind that storing the the MAC address in Active Directory means that all of the users in your domain will have read access to it which in turn might possibly (depending on your environment) pose a small security risk.
To do it the way the network does.
Grab SharpPcap (Pcap wrapper for C#) and WinPcap (Windows) or libpcap (*nix). Write an application that creates SNMP packets to query the ARP table on the router.
Note: The ARP (Address Resolution Protocol) table is the table containing the mapping of IP address to MAC address.
I've been thinking about implementing an example that does this lately but I don't have one to show yet. Once I do, I'll make sure it gets added to the SharpPcap examples found in the project's source tree.
You can't do that with DHCP. DHCP attributes IP from MAC, not the other way around.
ARP is what converts IP into MAC but it's the machine itself that answers ARP requests so if it's off it's obviously not gonna answer ...
I suggest you store the MAC in your AD directly (I guess AD supports custom attributes ?)
you need to use arp to get a mac adress and doing so In C is a long process.
Mac adresses are hard coded, so if you have X computers go and get X mac addresses and tie them to the AD.
Note that the computer will have to be on to request its mac address.
Finding MAC address from IP address
Yeah dun worry about it, you can pull this info directly from DHCP if the PC has a lease.
Know how you right click and add a reservation in DHCP?
Look in DHCP for the 'unique ID'. It's the MAC address, sans the colons.
Greetings,
I need a way (either via C# or in a .bat file) to get a list of all the computers on a given network. Normally, I use "net view", but this tends to work (from my understanding) only within your domain. I need the names (or at least the IP Addresses) of all computers available on my network.
Being able to get all computers on a domain that isn't mine (in which case I'd use WORKGROUP, or whatever the default is) would also work.
Nmap is good for this - use the -O option for OS fingerprinting and -oX "filename.xml" for output as xml that you can then parse from c#.
A suitable commandline would be (where 192.168.0.0/24 is the subnet to scan):
nmap -O -oX "filename.xml" 192.168.0.0/24
leave out the -O if you aren't interested in guessing the OS - if you just want a ping sweep use -sP, or read the docs for the myriad other options.
To expand on what Unkwntech has said -
You can also do a "broadcast" ping to avoid having to ping each IP address individually.
Immediately after than you can use "arp" to examine the ARP cache and get a list of which IP addresses are on which MAC address.
Ping everything in the rage, then you can get netbios info from the systems that respond to identify it's name.
In one of my web app I used the NetApi32 function for network browsing.
Code:
http://gist.github.com/11668