Dear Community
In Leap 42.3 I did the following setting … 
https://picload.org/view/dcrgilri/2018-10-06_09-33-22.png.html
I have no Idea where to set this in the new Firewall-Application of Leap 15.0. 
Any help is welcome.
Thanks in advance; PATRICK
Yes, as the release notes hint at firewalld is now used by default…
https://doc.opensuse.org/release-notes/x86_64/openSUSE/Leap/15.0/#sec.package.removed
SuSEfirewall2: Replaced by firewalld. For information about migrating to firewalld, see https://en.opensuse.org/Firewalld and https://doc.opensuse.org/documentation/leap/security/html/book.security/cha.security.firewall.html#sec.security.firewall.firewalld.
Firewalld has a graphical configuration front-end (firewall-config package if not already installed) that offers the simplest way to adjust the firewall to your needs. It also offers a CLI utility (firewalld-cmd) which takes a bit more learning.
Are you wanting to allow UDP traffic from 192.168.1.78? If so, check out adding a ‘rich rule’…
https://major.io/2014/11/24/trust-ip-address-firewallds-rich-rules/
Alternatively using firewall-cmd, perhaps something like the following…
sudo firewall-cmd --zone=public --add-rich-rule='rule family="ipv4" protocol value="udp" source address="192.168.1.78" accept' --permanent
sudo firewall-cmd --reload
A good tutorial for getting a hang of the basics…
https://www.digitalocean.com/community/tutorials/how-to-set-up-a-firewall-using-firewalld-on-centos-7