[fancyfredbot]

It feels like the article ends with a cliffhanger!

Why did a single packet of the custom protocol get through with all later packets dropped? Does anyone know?

[kazen44]

my guess is the first packet got through a firewall, which created a flow.

subsequent packets then got blocked because the firewall has no way of matching this to an existing flow.

[m3talsmith]

Definitely the most likely

[wrs]

Yeah! I am baffled that even one got through, but given that it did, why only one? And I would’ve immediately tried the “every protocol” version at that point…