Association delay between Windows and Linux

[Maryam]

Dear friends,

I’ve encountered a problem while using dcmnet.That’s when the storescp run on Windows machine and the storescu run on a Linux machine, It makes a 7-8 seconds delay to make an association on some machines ( specially laptops) while on another machine, delay is trivial. It’s strange that if storescp and storescu both run on windows machines or both run on linux machines, no delay happens! I’m really wondered what the problem is.

I’m sure that all firewalls are off and IPtables service is disable but when the scu asks an association to send the image, a bothering delay occurred. May it related to hardware? Because it works well on some machines! ( I also disabled host lookup ).

[Marco Eichelberg]

When DNS look-up, firewall and IP filter are off, I have no real answer to your question (all of the factors mentioned above are known to be possible reasons for such delays). It would probably be necessary to do some very low-level debugging at the level of socket functions to see in which system functions the delay arises - most likely during the TCP connection set-up which is not DCMTK specific but simply part of the operating system, but this is not more than a wild guess.

[Maryam]

Thanks, the problem was related to DNS look-up. It was strange that I always used IP address not computer name but on some machines the program still seeks for DNS even when server is called using IP address.

Anyway, my program for both Store and Move commands is running normal and without any delay when I add the following function:

dcmDisableGethostbyaddr.set(OFTrue);

[Marco Eichelberg]

Many DCMTK applications have a command line option named --disable-host-lookup for this purpose.