No DHCP server found (stable/12 & stable/13)

(This may also apply to head; I haven't tested it recently, and testing
is a little awkward for me just now. -- dhw)

As I type, I am 9 time zones east of home.  The laptop I am using is
running:

FreeBSD localhost 13.1-STABLE FreeBSD 13.1-STABLE #468 stable/13-n250522-48a5e3fc6568: Wed Apr 20 05:25:39 PDT 2022     root@g1-48.catwhisker.org:/common/S3/obj/usr/src/amd64.amd64/sys/CANARY amd64 1301501 1301501

I have seen an apparently-similar set of symptoms on a different laptop
(that I use for the bulk of my day-to-day activities when I am not
wandering about (e.g., in different time zones)); it was running:

FreeBSD 12.3-STABLE #1236 stable/12-n235174-879a6b7b628: Tue Apr 19 03:32:12 PDT 2022     root@g1-70.catwhisker.org:/common/S1/obj/usr/src/amd64.amd64/sys/CANARY  amd64 1203507 1203507

when I last observed the issue.

In each case, I have no problems associating (if using wireless) and
acquiring a DHCP lease at home (where the DHCP server is
net/isc-dhcp44-server (isc-dhcp44-server-4.4.2P1_1), currently running:

FreeBSD 12.3-STABLE #59 stable/12-n235169-6def5bc64cb: Fri Apr 15 03:31:41 PDT 2022     root@freebeast.catwhisker.org:/common/S1/obj/usr/src/amd64.amd64/sys/ALBERT  amd64 1203507 1203507

), nor do I see the problem if I have either laptop associate to my
phone's "hotspot".

But at the hotel where I am no, as well as on the commuter shuttle bus
at work, and a hotel in Los Angeles back in March, I found that dhclient
on the laptop would issue DHCPDISCOVER (repeatedly)... and utterly fail
to recognize any response from a DHCP server.

In searching for solutions, I found a thread, " dhclient does not decode
802.1q-encapsulated replies #114 " at
https://github.com/opnsense/src/issues/114 - I have no idea if it's
related to what I am seeing.  (While I don't use OPNSense, I do use
ipfw (and have, since around 1999).  I am not at all familiar with VLANs
-- I don't use them in my networks.)

I do use an /etc/dhclient.conf; here are the non-comment lines:

| send host-name "";
| 
| request ntp-servers, smtp-server, routers, domain-name-servers, domain-search, domain-name, subnet-mask, broadcast-address;

though the mtime on that file shows Aug 15 04:40:08 2018 (at which point
I know the shuttle bus DHCP was working for me).

As you may be able to discern, while I do have connectivity enough
to send/receive email, my opportunities for checking and testing
are likely to be quite limited -- more so in a couple of days, once
the cycling tour actually gets under way.

Peace,
david
-- 
David H. Wolfskill                              david@catwhisker.org
V. Putin does not need "negotiations" to stop his own senseless war.

See https://www.catwhisker.org/~david/publickey.gpg for my public key.