concerning our discussion of the LMC (and other) network difficulties: I highly recommend to get a knowledgeable networking tech on-site. I can’t tell for sure, but I believe your network setup does contain kinks and knots giving you the troubles you’re reporting about. And it’s starting to get to a level of detail where public and remote discussions lack the required possibilities.
It seems like you’re in Finland, that’s a bit far off from Hamburg to pay an afternoon visit, but maybe you can find some help either in your company or at least close by?
When you have some low-level “inconsistencies” in your network setup, you can easily get into deep trouble, causing tons of work for debugging at higher levels without actually getting anywhere. Just my 2 cents…