This package requires zeek-known-hosts-with-dns. You will also need comment out ssh/interesting-hostnames from the default local.bro/local.zeek file.
The default ssh/interesting-hostnames policy does dns lookups for the source host of every successful ssh authentication. In our environment, the majority of ssh connections are internal and, due to automation, there are a lot of them. This results in Zeek making thousands of asynchronous when() calls for lookup_addr().
By replacing known-hosts with known-hosts-with-dns, we keep a running table of local DNS lookups. Combined with this policy, it can reduce the DNS queries from our Zeek systems by over 90%.