Ikea siphon connection for dishwasher or washing machine?

Not necessarily. For example, Atlant could already be combined with Blanco parts.
Regards,
IKEA-Freund

So the siphon is not the same, it has already been improved with a cleaning valve and brackets. I also find the missing second connection stupid. However, there is an "official" DIY guide with a Y-piece (from Bauhaus or Amazon) and metal clamps. Elegant is something else, and if you're not careful, the whole thing is not airtight.

No, unfortunately not. IKEA has its own measurements and the standard diameters are incompatible. That is exactly my frustration.

Not at the connection! Only the drain itself!