On a NanoBSD appliance running as gateway/router/firewall, I use a for efficiency restricted setup. The onboard utility /usr/sbin/tcpdump is NOT one of the restricted and therefore not installed binaries, but obviously it is non-functional due to some weird library dependencies.

Calling /usr/sbin/tcpdump results in the error

ld-elf.so.1: Shared object "libibverbs.so.1" not found, required by libpcap.so.8"

Checking 

ldd /usr/sbin/tcpdump

results in 

/usr/sbin/tcpdump:
        libpcap.so.8 => /lib/libpcap.so.8 (0x800338000)
        libcasper.so.1 => /lib/libcasper.so.1 (0x80039d000)
        libcap_dns.so.1 => /lib/casper/libcap_dns.so.1 (0x8003a4000)
        libcrypto.so.111 => /lib/libcrypto.so.111 (0x8003ab000)
        libc.so.7 => /lib/libc.so.7 (0x8006ad000)
        libibverbs.so.1 => not found (0)
        libmlx5.so.1 => not found (0)
        libnv.so.0 => /lib/libnv.so.0 (0x800ab3000)
        libthr.so.3 => /lib/libthr.so.3 (0x800ac7000)

This is a kind of embarassing, I do not need any mlx driver/libs nor do I have them loaded/installed (kernel module load is prohibited anyway).

I see this weirdness also with arpwatch.