Import of IGES / DNS request

Hi all,

when I import an IGES file, my firewall (Zonealarm) indicates, that my software tries to access a DNS service on a remote host. (I will post the IP later)

I am absolutely sure, that this happens within the OpenCascade (Version 5.0) libraries - verified in a debug session.

Can anyone confirm this and why does this happen ?

Kind regards

Markus Nickels

Forum supervisor's picture

Hello Markus,
I am afraid nobody will confirm this strange observation...
Anyway, OCC is an Open Source - please take your time to analyze its code for the possible IP calls.
Good luck!

Markus Nickels's picture

I have investigated it a little bit more:

The DNS request occurs in the Constructor IGESControl_Reader and the requested IP is which translates to

Sorry, but I've no idea where it comes from ...


Patrik Mueller's picture


if I remember right the IGES classes depends on the defined STEP entities. And in STEP the writer writes out the hostname. So perhaps it uses the DNS for finding the hostname even if you don't write STEP?
If you are online at this moment you'll have the IP address from your provider e.g. T-Online.