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Jeromq on Windows 7 creates more than 20 ports when a socket is created.
The jdk version is 1.8.0_51 (64bit) version. OS is windows 7 x64. The jeromq version is 0.3.5.
Note, the same behavior is not exhibited on OSX.
Here is the dump from the tcpview. And only the ports 5556 (PULL) and 5557(REP) should be open.
java.exe 11216 TCP MACHINE1 59542 localhost 59544 ESTABLISHED 1 8
java.exe 11216 TCP MACHINE1 59543 localhost 59545 ESTABLISHED 1 8
java.exe 11216 TCP MACHINE1 59544 localhost 59542 ESTABLISHED
java.exe 11216 TCP MACHINE1 59545 localhost 59543 ESTABLISHED
java.exe 11216 TCP MACHINE1 59546 MACHINE1 0 LISTENING
java.exe 11216 TCP MACHINE1 59547 MACHINE1 0 LISTENING
java.exe 11216 TCP MACHINE1 59548 localhost 59546 ESTABLISHED
java.exe 11216 TCP MACHINE1 59549 localhost 59547 ESTABLISHED
java.exe 11216 TCP MACHINE1 59550 localhost 59552 ESTABLISHED 1 8
java.exe 11216 TCP MACHINE1 59551 localhost 59553 ESTABLISHED 1 8
java.exe 11216 TCP MACHINE1 59552 localhost 59550 ESTABLISHED
java.exe 11216 TCP MACHINE1 59553 localhost 59551 ESTABLISHED
java.exe 11216 TCP MACHINE1 59554 localhost 59555 ESTABLISHED 1 8
java.exe 11216 TCP MACHINE1 59555 localhost 59554 ESTABLISHED
java.exe 11216 TCP MACHINE1 59556 MACHINE1 0 LISTENING
java.exe 11216 TCP MACHINE1 59557 localhost 59558 ESTABLISHED 1 8
java.exe 11216 TCP MACHINE1 59558 localhost 59557 ESTABLISHED
java.exe 11216 TCP MACHINE1 59559 localhost 59556 ESTABLISHED
java.exe 11216 TCP MACHINE1 59560 localhost 59561 ESTABLISHED 1 8
java.exe 11216 TCP MACHINE1 59561 localhost 59560 ESTABLISHED
java.exe 11216 TCP MACHINE1 59562 localhost 59563 ESTABLISHED 1 1 1 8
java.exe 11216 TCP MACHINE1 59563 localhost 59562 ESTABLISHED
java.exe 11216 TCP MACHINE1 59564 localhost 59567 ESTABLISHED 1 8
java.exe 11216 TCP MACHINE1 59565 localhost 59566 ESTABLISHED 1 8
java.exe 11216 TCP MACHINE1 59566 localhost 59565 ESTABLISHED
java.exe 11216 TCP MACHINE1 59567 localhost 59564 ESTABLISHED
java.exe 11216 TCP MACHINE1 59568 localhost 59569 ESTABLISHED 1 8
java.exe 11216 TCP MACHINE1 59569 localhost 59568 ESTABLISHED
java.exe 11216 TCP MACHINE1 59570 localhost 59573 ESTABLISHED 1 1 1 8
java.exe 11216 TCP MACHINE1 59571 localhost 59572 ESTABLISHED 1 1 1 8
java.exe 11216 TCP MACHINE1 59572 localhost 59571 ESTABLISHED
java.exe 11216 TCP MACHINE1 59573 localhost 59570 ESTABLISHED
java.exe 11216 TCP MACHINE1 59574 localhost 59575 ESTABLISHED 1 8
java.exe 11216 TCP MACHINE1 59575 localhost 59574 ESTABLISHED
java.exe 11216 TCP MACHINE1 5556 MACHINE1 0 LISTENING
java.exe 11216 TCP MACHINE1 59576 localhost 59577 ESTABLISHED 1 8
java.exe 11216 TCP MACHINE1 59577 localhost 59576 ESTABLISHED
java.exe 11216 TCP MACHINE1 59578 localhost 59579 ESTABLISHED 1 1 1 8
java.exe 11216 TCP MACHINE1 59579 localhost 59578 ESTABLISHED
java.exe 11216 TCP MACHINE1 59580 localhost 59581 ESTABLISHED 1 8
java.exe 11216 TCP MACHINE1 59581 localhost 59580 ESTABLISHED
java.exe 11216 TCP MACHINE1 5557 MACHINE1 0 LISTENING
I have done a similar testing with Python PyZMQ to compare the jeromq with native zeromq implementation. In native ZeroMQ, when a context is created, there were 2 TCP ports open. When a socket is created for that context, 6 additional TCP ports were open. In the end, when a socket is bound to listening port, the port was open. In total, there are 9 TCP ports used, which is still 50% less than jeromq. I am wondering if there is a way to control the number of ports gets open by jeromq.
That seems odd. Unfortunately, I don't have a windows machine to test on to recreate this scenario. Hopefully, someone else from the community will be able to corroborate.
Information needed:
- An explanation from someone who understands this part of the code.
- In what part of the code are these ports ultimately created?
- Is there any place where it's possible that "duplicate" ports can be created?
- What does it mean to "create a port," exactly?
- Do we think this issue may have resolved in the almost-two-years since it was created?
It's been almost 3 years since this issue was created and we have no reports that it's still an issue with the latest version. Closing the issue for now -- feel free to reopen if the issue persists in the latest version of JeroMQ.
I am seeing the same thing with jeromq 0.4.3 on Windows 10, jdk 1.8.0_201.
AFAICT this is easily reproductible, it happens 100% of the time, tried on two separate machines.
Update to this issue: Five years after issue creation (nearly even to the day) the problem still exists in jeromq release 0.5.2.
I just created a test application with 'Simple example' code from README [https://github.com/zeromq/jeromq#simple-example] and I also can see 20 ports being open. My environment consists of Windows 10 and openjdk-12.
The strange thing is that the open ports are connected to each other mutually in pairs of two - so there are two times ten ports connected:
