Simultaneous connections are not possible with netcat. You should use something like ucspi-tcp‘s tcpserver tool or leverage xinetd since you’re on Linux. See: https://superuser.com/questions/232747/netcat-as-a-multithread-server Consecutive connections could be handled through a shell script that restarts netcat after it finishes.
There’s nothing wrong necessarily with grouping questions together, but it does make answering the question more challenging… 🙂 The MSDN article you linked shows how to do a one-and-done TCP communication, that is, one send and one receive. You’ll also notice it uses the Socket class directly where most people, including myself, will suggest using … Read more
Since there has been some interest in this question and no confirmations, I will just respond now. It has been a while since the tests were done, and a production level solution has been created and rigorously tested. Removing the wake lock still helped the battery and no other issues were found such as missing … Read more
There’s a very long answer to this in the Winsock Programmer’s FAQ. It details the standard setting, and the dynamic backlog feature added in a hotfix to NT 4.0.
Looks like this was added in Kernel 2.6.37. Commit diff from kernel Git and Excerpt from change log below; commit dca43c75e7e545694a9dd6288553f55c53e2a3a3 Author: Jerry Chu Date: Fri Aug 27 19:13:28 2010 +0000 tcp: Add TCP_USER_TIMEOUT socket option. This patch provides a “user timeout” support as described in RFC793. The socket option is also needed for the … Read more
In theory SMTP can be handled by either TCP, UDP, or some 3rd party protocol. As defined in RFC 821, RFC 2821, and RFC 5321: SMTP is independent of the particular transmission subsystem and requires only a reliable ordered data stream channel. In addition, the Internet Assigned Numbers Authority has allocated port 25 for both … Read more
For a TCP connection memory consumed depends on size of sk_buff (internal networking structure used by linux kernel) the read and write buffer for a connection the size of buffers can be tweaked as required root@x:~# sysctl -A | grep net | grep mem check for these variables these specify the maximum default memory buffer … Read more
You Just Can’t Beat the Binary Binary protocols will always be more space efficient than text protocols. Even as internet speeds drastically increase, so does the amount and complexity of information we wish to convey. The text protocols you reference are outstanding in terms of standardization, flexibility and ease of use. However, there will always … Read more
Turns out socat can be used to achieve this: socat TCP-LISTEN:1234,reuseaddr,fork UNIX-CLIENT:/tmp/foo And with a bit of added security: socat TCP-LISTEN:1234,bind=127.0.0.1,reuseaddr,fork,su=nobody,range=127.0.0.0/8 UNIX-CLIENT:/tmp/foo These examples have been tested and work as expected.
Absolutely. A standard server can handle more than 10K concurrent connections using the model with one thread per connection. I have build such an application, and five years ago, it was running with more than 50K concurrent connections per process on a standard Linux server. Nowadays, it should be possible to run the same application … Read more