No ARP Table, and a DNS issue.

I have an (embedded) linux device which is trying to communicate with
a URL (e.g. When I wireshark the output
from the eth0, all I see is an ARP request for the default gateway,
which is never resolved. When I view the ARP table (arp, arp
neighbor, etc), Linux tells me it doesn't recognise the command.

This may be related, or may not. If I ty to ping an IP address, it
works fine. If I try to ping the URL associated with the IP address,
it doesn't. Sounds like a DNS problem. So, I checked /etc/
resolve.conf, but this is fine.

Other machines (admittedly, no embedded), don't have these problems.
Kernel was build using buildroot, and busybox, on a Fedora Linux