[tor-relays] Limiting connection count

Hi,

I'm running a Tor relay on a Raspberry 2 behind a router using port forward. Relay bandwidth is set to 1 MByte / second. Tor is accepting so many connections that my Raspi can't keep up and my router is getting very slow (I assume because of a crappy NAT implementation). Bandwidth is not an issue, its the open connection count.

Is there a way to limit the maximum number of connections? I tried to apply a ulimit on open files via systemd, but Tor is then showing a warning.

At the moment I run a iptables rule which restricts the connection count to port 9001 (OR port) to 1000. But I'm not sure how this will affect the relay, for example Tor Metrics is showing the relay as offline.

BR, Moritz