[WinMac] Mac DHCP client <-> NT DHCP Server follow-up
Daniel L. Schwartz(expresso[at]snip.net)
Fri, 23 Apr 1999 23:58:44 -0500
So, according to Mr. Droms, it *was* Apple screwing up on
this important issue, after all, by having the client starting in
INIT-REBOOT state *after* sending a DHCPRELEASE message upon previous
Mac shutdown.
Thanks are due to Mr. Droms and Ric Ford for bringing this
problem to a close.
Dan Schwartz
>>>>
>DHCP Standards
>Date: Sun, 18 Apr 1999 21:39:11 -0400
>To: notes@macintouch.com
>From: Ralph Droms (droms@bucknell.edu)
>Subject: DHCP problems with MacOS 8.5 and OT 2.02
>
>
>I'm writing in response to what appears to be considerable confusion
>about DHCP, OT 2.02 and various servers. I'm chair of the Dynamic
>Host Configuration working group (DHC WG) of the IETF and author of
>the DHCP specs. Here are some notes about the DHCP mail you posted
>recently.
>
>
>- Ralph Droms
> Chair, IETF DHC working group
> Computer Science Department
> Bucknell University
>
>
>
>
>* According to RFC 2131, when a DHCP client restarts, it is either
>in INIT state or INIT-REBOOT state. If the client doesn't have an IP
>address, it starts in INIT state and broadcasts a DHCPDISCOVER
>message to find a server willing to assign an address to the client.
>If the client has an IP address with an unexpired lease, it starts
>in INIT-REBOOT state and the client broadcasts a DHCPREQUEST message
>to confirm that its address is still valid.
>
>* There is another aspect to the behavior of the OT 2.02 client that
>has only recently been documented (Internet Draft
>draft-ietf-dhc-ipv4-autoconfig-04.txt). If the OT client receives no
>response to a DHCPDISCOVER message in INIT state, the client will
>select an address from the 169.254.0.0 subnet, which has been
>registered with IANA as the LINKLOCAL subnet. Recent Windows DHCP
>clients also use this autoconfiguration mechanism.
>
>* There was some not quite correct information about DHCP clients in
>one of the [reader notes]. A DHCP client always tries to contact a
>server when it restarts, whether or not it has an address with an
>unexpired lease, as described above. If a client in INIT-REBOOT
>state receives no response to its DHCPREQUEST messages, it assumes
>that its address is OK and continues to use its old address. Sending
>a DHCPRELEASE message is optional on the part of the client. If the
>client will not reuse the address again (i.e., the client is moving
>to a new network segment) or is willing to obtain a new address when
>it restarts, it may issue a DHCPREQUEST and restart in INIT state;
>otherwise, the client may remain silent at shutdown and restart in
>INIT-REBOOT state.
>
>* Based on RFC 2131, the behavior of OT 2.02, in which it restarts
>in INIT-REBOOT state after issuing a DHCPRELEASE at the previous
>shutdown, is incorrect. I've been in communication with the DHCP
>team at Apple; they understand that this behavior is incorrect and
>they plan to correct it.
>
>* When starting (incorrectly) in INIT-REBOOT state, after receiving
>no server response, the OT 2.02 Macs are following RFC 2131 and
>using their previous address. I'm a little surprised that the
>servers in question don't respond to the DHCPREQUEST for a released
>address with a DHCPNAK message. I'm also a little surprised that
>these Macs then revert to INIT state at the next use of OT; perhaps
>the lease on the reused address has timed out and the Mac was unable
>to extend the lease?
>
>
>
>[Follow-up]
>
>Date: Mon, 19 Apr 1999 08:32:23 -0400
>To: Ric Ford
>From: Ralph Droms
>
>
>There is an IETF page for the DHC WG,
>http://www.ietf.org/html.charters/dhc-charter.html and I run a
>DHCP-related site at http://www.dhcp.org
>
>- Ralph
>
>
>
>Rainoff Summary
>Date: Tue, 20 Apr 1999 16:21:17 -0400
>From: Adam Rainoff
>To: notes@macintouch.com
>Subject: DHCP and 8.5.1 comments
>
>
>Editor: I noticed much technical info posted. However, for the
>nontechnical, let me suggest the following post.
>
>Regarding the DHCP Issue & Mac OS 8.5.1
>
>The Bad news:www.P Issue & Mac OS 8.5.1
>
>Mac 0S 8.5.1 has a problem maintaining DHCP connections. This is the
>reason your ADSL or other DHCP service "drops". It's really not the
>provider's fault at all.
>
>The Good news:www.t all.
>
>Mac OS 8.6 fixes this problem, not only with ADSL, but with ALL DHCP
>services. The 8.6 update is scheduled for release sometime soon.
>
>Workaround:
>
>Reset your IP address by
>
>1) Open the TCP/IP control panel
>2) Change to "Using BootP Server"
>3) Close & Save
>4) Open the TCP/IP control panel
>5) Change to "Using DHCP Server"
>6) Close & Save
>
>
>Repeat if necessary. This will reset the IP and get you back online.
>
>
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