Re: renumbering and roaming
From: "Michael S. Fischer" <otterley@iPass.COM> In message <19980518135928.37530@mcs.net>, Karl Denninger writes:
That doesn't work; too many of those things must be hard-coded numbers (specifically, the DNS servers).
What has to be hard-coded besides the DNS servers? Once you have a DNS server assigned (which is typically done by the NAS anyway) the rest is simple.
Ideal World: Nothing should be hard coded. Every NAS should support DHCP and DHCP INFORM. Each roaming user simply sends a DHCP multicast / broadcast packet, which is intercepted and forwarded by the NAS (serial link) or the local router (LAN), and recieves a list of services, including DNS. This is the direction that many of us in the IETF have been advocating for about 11 years.... Real World: Although all the early (circa '89-92) NAS's supported BOOTP/DHCP relaying, more recent shoe-string NAS vendors are missing it, and clients have not universally implemented DHCP. We have to tell our customers the list of local DNS (and other) servers for them to type into their configuration (or we use a standard install CD). For this latter scenario, a few default universal hardcoded numbers would be a great idea! It would help with legacy clients, it would help roaming, and would not hurt as DHCP gets installed base. I look forward to reading the internet-draft. It should require no changes to client or server software.
In our experience, well over 90% of roaming users (which excludes UNIX and Mac users) use dynamically-assigned DNS servers. Clearly this approach won't work for those clients that don't support the LCP extensions, but we consider this "Best Current Practice." Those clients that can't use dynamic DNS server assignment will have to use the home ISP's services.
Speaking as the author of "LCP Extensions", there is no such LCP extension as "dynamically-assigned DNS servers". There is a bogus, NDA'd, Mircosoft-only, NetBEUI extension to PPP IPCP, using numbers stolen from the high end of the option space without registering with IANA, which is marginally applicable to DNS. This approach has been officially rejected by the IETF. It is not a "best current practice". It only works with NT servers, which no sane and stable ISP would use.
We consider it important to make sure as many NASes and PPP clients as possible support dynamic DNS. About the only major obstacle to that is OT/PPP (MacOS) and, to a lesser degree, UNIX.
AFIAK, Dynamic DNS is _only_ supported by Unix, but I have high hopes to see it on MacOS, now that Vinnie is back at Apple. I have no idea why it would be supported by a NAS or PPP client. I think you have your terminology wrong.... WSimpson@UMich.edu Key fingerprint = 17 40 5E 67 15 6F 31 26 DD 0D B9 9B 6A 15 2C 32
On 19 May 1998 08:06:24 -0400, William Allen Simpson <wsimpson@greendragon.com> wrote: |Speaking as the author of "LCP Extensions", there is no such LCP |extension as "dynamically-assigned DNS servers". | |There is a bogus, NDA'd, Mircosoft-only, NetBEUI extension to PPP IPCP, |using numbers stolen from the high end of the option space without |registering with IANA, which is marginally applicable to DNS. | |This approach has been officially rejected by the IETF. It is not a |"best current practice". It only works with NT servers, which no sane |and stable ISP would use. FWIW, almost all of the NAS's in production today support Microsoft's PPP extensions for dynamically assigned DNS servers. Like it or not, it's something that we have to live w/today. -- ------------------------------------------------------------------------- "The internet, of course, is more than a place to find pictures of people having sex with dogs" -- Philip Elmer Dewitt, Time Magazine, July 3, 1995 ------------------------------------------------------------------------- blahblahblah@oneill.net coneill@erols.com
At 2:44 PM -0400 5/19/98, Clayton O'Neill wrote:
On 19 May 1998 08:06:24 -0400, William Allen Simpson <wsimpson@greendragon.com> wrote: |Speaking as the author of "LCP Extensions", there is no such LCP |extension as "dynamically-assigned DNS servers". | |There is a bogus, NDA'd, Mircosoft-only, NetBEUI extension to PPP IPCP, |using numbers stolen from the high end of the option space without |registering with IANA, which is marginally applicable to DNS. | |This approach has been officially rejected by the IETF. It is not a |"best current practice". It only works with NT servers, which no sane |and stable ISP would use.
FWIW, almost all of the NAS's in production today support Microsoft's PPP extensions for dynamically assigned DNS servers. Like it or not, it's something that we have to live w/today.
Really? I can't seem to find it in the USR manuals. --Dean ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Plain Aviation, Inc dean@av8.com LAN/WAN/UNIX/NT/TCPIP/DCE http://www.av8.com We Make IT Fly! (617)242-3091 x246 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
On Wed, 20 May 1998, Dean Anderson wrote:
FWIW, almost all of the NAS's in production today support Microsoft's PPP extensions for dynamically assigned DNS servers. Like it or not, it's something that we have to live w/today.
Really? I can't seem to find it in the USR manuals.
Yep: NetServer 5> help set nasdns_info Usage: set nasdns_info on|off Charles
--Dean
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Plain Aviation, Inc dean@av8.com LAN/WAN/UNIX/NT/TCPIP/DCE http://www.av8.com We Make IT Fly! (617)242-3091 x246 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
FWIW, almost all of the NAS's in production today support Microsoft's PPP extensions for dynamically assigned DNS servers. Like it or not, it's something that we have to live w/today.
Really? I can't seem to find it in the USR manuals.
--Dean
AFAIK from our testing it is there... if people are really interested I can find out more from a colleague. Peter
On Wed, May 20, 1998 at 12:23:18AM -0400, Dean Anderson wrote:
At 2:44 PM -0400 5/19/98, Clayton O'Neill wrote:
On 19 May 1998 08:06:24 -0400, William Allen Simpson <wsimpson@greendragon.com> wrote: |Speaking as the author of "LCP Extensions", there is no such LCP |extension as "dynamically-assigned DNS servers". | |There is a bogus, NDA'd, Mircosoft-only, NetBEUI extension to PPP IPCP, |using numbers stolen from the high end of the option space without |registering with IANA, which is marginally applicable to DNS. | |This approach has been officially rejected by the IETF. It is not a |"best current practice". It only works with NT servers, which no sane |and stable ISP would use.
FWIW, almost all of the NAS's in production today support Microsoft's PPP extensions for dynamically assigned DNS servers. Like it or not, it's something that we have to live w/today.
Really? I can't seem to find it in the USR manuals.
--Dean
That figures and is not surprising at all. Lucent/Livingston and ASCEND both do support it. Of course, between the two of them they're easily a majority of the market. -- -- Karl Denninger (karl@MCS.Net)| MCSNet - Serving Chicagoland and Wisconsin http://www.mcs.net/ | T1's from $600 monthly / All Lines K56Flex/DOV | NEW! Corporate ISDN Prices dropped by up to 50%! Voice: [+1 312 803-MCS1 x219]| EXCLUSIVE NEW FEATURE ON ALL PERSONAL ACCOUNTS Fax: [+1 312 803-4929] | *SPAMBLOCK* Technology now included at no cost
Speaking as the author of "LCP Extensions", there is no such LCP extension as "dynamically-assigned DNS servers".
There is a bogus, NDA'd, Mircosoft-only, NetBEUI extension to PPP IPCP, using numbers stolen from the high end of the option space without registering with IANA, which is marginally applicable to DNS.
This approach has been officially rejected by the IETF. It is not a "best current practice". It only works with NT servers, which no sane and stable ISP would use.
The sad fact is that this what what most people use. It may as well be a standard, since it works. I hate M$ as much as the next clueful person, but you need to know your enemy before making statements like this. The assignments of DNS during PPP IPCP is not restricted to NT, but works on the other M$ OSes and also a large number of non WinCE PDAs too. No matter how technically inelegant, the solution is one that works, uses minimum overhead and can be driven from that simple configuration engine, "RADIUS". You may also now argue that RADIUS is an user authentication database, but it is being used, again, in the real world, as a configuration database, and users just happen to be one of those items being configured. Peter
participants (6)
-
Charles Sprickman -
Dean Anderson -
Karl Denninger -
Peter Galbavy -
usenet＠oneill.net -
William Allen Simpson