The Raspberries do not have any firewall.
The firewall is configared that ICMP and SSH is allowed.

Dear Sir or Madams,

I have problems to connnect to Rasperry Pis with SSH.

When the Rasperries are directly through a switch connected to my device the ssh connection works. So the SSH-configuration of my Raspberries should be right.
If I want to connect them through a VLAN (so without routing) it ...