[gentoo-user] Both ssh and nfs.mount are sending an obsolete ip address

[walt]

I just updated my older ~amd64 machine and I'm seeing weird behavior when
using nfs and ssh services to communicate with my newer ~amd64 machine.

Both mount.nfs and ssh are telling my newer machine that they are talking
from an obsolete ip address :/

To clarify:  my wireless router dispenses ip addresses based on some formula
I don't understand, but it clearly depends on which method each localhost
uses to contact the wireless router.

i.e. does it use dhcpcd, or dhcpd, or some other method invoked by systemd
or maybe wpa_supplicant?

So, looking at the system logs on the newer machine, I can see that the older
machine is advertising (somehow) that it's still using an ip address that *was*
correct in the past, but now my wireless router has assigned a newer one due to
some updated package (no idea which package).

To be specific:  nfs.mount is claiming that its clientaddr is the old address,
and ssh is claiming that its rhost is also the same old address.

So, how are these two different packages claiming the same, obsolete, ip address?
Where are they getting it?  It must be cached somewhere on the older machine, but
where?