Hello,
We had made an internal RUTX IPsec test. The following results were acquired by using SSH/CLI and WEBUI may impose other restrictions:
IPsec can support up to 2000 tunnels and can be more if given enough setup time, but not recommended.
These limits are just for established connections and do not guarantee flawless performance when real-world traffic is introduced, which will drop these numbers depending on how heavy the load is.
Note, that when approaching the client count limit, the router may start having performance issues and services might even crash. Also, these tests were done in mostly an ideal scenario, with only default services running, so enabling additional services will most likely reduce the client count limit.
Regards.