How does named pipes work

Finally - as mentioned in the introduction - Named Pipes can also be used over a network connection across system boundaries. There are no additional implementations needed to call a remote Named Pipe server, just make sure that your call to CreateFile specifies an IP or hostname as with the example above. An SMB connection is made to the remote server, which is by default initialized by a negotiation request to determine the network authentication protocol.

Unlike with other IPC mechanisms, such as with RPC, you as a server developer can not control the network authentication protocol as this is always negotiated through SMB. Since Kerberos is the preferred authentication scheme since Windows , Kerberos will be negotiated if possible. Note: From a client perspective you can effectively choose the authentication protocol by choosing to connect to a hostname or to an IP.

Due to the design of Kerberos it cannot handle IPs very well and as such if you choose to connect to an IP address the result of the negotiation will always be NTLM v2. Whereas when you connect to a hostname you will most likely always end up using Kerberos. Once the authentication is settled, the actions that client and server want to perform are once again just classic file actions, that are handled by SMB just as any other file operation, e.

In byte mode , messages travel as a continuous stream of bytes between the client and the server. This means that a client application and a server application do not know precisely how many bytes are being read from or written to a pipe at any given moment. Therefore a write on one side will not always result in a same-size read on the other.

This allows a client and a server to transfer data without caring about the size of the data. In message mode , the client and the server send and receive data in discrete units. Every time a message is sent on the pipe, it must be read as a complete message. Therefore I will add these concepts here briefly. More details on this can be found here with a sample implementation by Microsoft here.

The blocking mode behavior is defined when setting up a named pipe server with CreateNamedPipe by using or omitting a flag in the dwPipeMode parameter. The following two dwPipeMode flags define the blocking mode of the server:.

When performing read and write operations your named pipe server uses non-paged memory meaning physical memory to temporarily store data which is to be read or written. An attacker who is allowed to influence these values for a created server can abuse these to potentially cause a system crash by choosing large buffers or to delay pipe operations by choosing a small buffer e. The only gear you can turn when you want to secure your named pipe setup is setting a Security Descriptor for the named pipe server as the last parameter lpSecurityAttributes to the CreateNamedPipe call.

The Windows docs define what the default Security Descriptor does for your named pipe server:. The ACLs in the default security descriptor for a named pipe grant full control to the LocalSystem account, administrators, and the creator owner. They also grant read access to members of the Everyone group and the anonymous account. For remote connections, note once again - as described at the end of the Named Pipe Messaging chapter - that the network authentication protocol is negotiated between the client and server through the SMB protocol.

There is no way to programmatically enforce the use of the stronger Kerberos protocol you only could disable NTLM on the server host. Impersonation is the ability of a thread to execute in a security context different from the security context of the process that owns the thread. Impersonation typically applies in a Client-Server architecture where a client connects to the server and the server could if needed impersonate the client.

Identify which enviorment you fit into and only enable the bare number of protocols, for the "I don't sleep much" network or db administrator you might even want to check it all the way down to each and every connection being made. It's obviously not only a server-side performance issue. I believe my questions are more related to networking than SQL Server.

So, the information in BOL does not really address my questions. The reason I ask about 2 "When will Named Pipes use port and when will it use port ? Note: I'm guessing that the problem may be related to Name Resolution. You must be logged in to reply to this topic. Login to reply. Skip to main content.

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