i am experiencing changes in the ratio of incoming and outgoing connections, i.e.: yesterday, i had no outgoing connections, today, i have no incoming connections.

i have changed nothing in the configuration.

can someone explain the dynamics within the gnutella protocol and why these things happen (in simple words)?

i mean, i always start with a first outgoing connection, then my ip is "discovered", i.e. known to a few hosts in the network and propagated to other clients. theoretically, i could be accepting incoming connections now.

I think this is a thing of chance... with one exception:
A gnutella-client behind a firewall often can reach the network only by outgoing connections.

So if all of your connections are to firewalled clients of this kind, all your connections are incoming.

For sure, some Firewalls have an open port for gnutella. Then the client behind can be reached by incoming connections. But many firewalls are not opened for gnutella!