Date: Fri, 19 Nov 1999 18:31:46 -0500 From: "Eric W. Bates" <ericx@vineyard.net> To: Nathan Mahon <vaevictus@socket.net> Cc: freebsd-isp@FreeBSD.ORG Subject: DHCP, win95 clients and more fun. Message-ID: <199911192331.SAA08946@apache.vineyard.net> In-Reply-To: <Pine.LNX.4.10.9911170926360.3396-100000@nathanm.office.socket.net> References: <Pine.LNX.4.10.9911170926360.3396-100000@nathanm.office.socket.net>
next in thread | previous in thread | raw e-mail | index | archive | help
Please excuse if I am way off in left field. I'm making a few guesses
between the lines of your note. I don't think your client's machines
are getting their configs.
You cannot use dhcp to assign addresses in a network space if there is
no interface to that network. This holds true for both your networks
10.0.1.0/24 and 10.0.2.0/24. You will have to hang an IP from each
network on your NIC (or loopback). You will also need a mechanism to
distinguish each DHCP REQUEST sufficiently so that your DHCP server
can decide which of the multiple networks the NIC touches is the
appropriate one from which to assign an IP (the packet is being sent
to FFFF.FFFF.FFFF.FFFF with little more than its own MAC number to
identify itself.
You might also consider renumbering altogether. There are way too
many devices defaulting to 10.0.0.0/24. Some one of your customers
downstream is likely to install Windows NT Small Business Services
(you think NT is bad...). The SBS proxy dhcp server defaults to
10.0.0.0/24 and even if the bindings are set to point the service at
only one of multiple interfaces, it will post an error and quit if it
sees any DHCP activity using 10.0.0.0/24 on the other interface. Net
10 gives you a whole class A to play with. I like to make something
up for each NAT'ed net, e.g. 10.12.34.0/24. It is useful to stick with
ye olde classic /24 nets because sometimes the gear is old or (just
crappy) and can't handle variably sized subnets and/or aggregation.
Also there is a problem betwixed Win95 and ISC-DHCP. After receiving a
broadcast packet from a machine in INIT state requesting DHCP info,
ISC's server will send the response back with the client's MAC address
instead of the ethernet broadcast address, FFFF.FFFF.FFFF, (after all,
why bother every machine on the net with a broadcast packet when you
know which machine wants the data?) but the packet has the IP
broadcast address, 255.255.255.255, because the client doesn't have an
IP yet (it's in the packet). Those with more smarts than I might
argue, but I agree with the ISC designers that this is "the right
thing". However, it is a violation of IP protocol in that ARP wants
the 2 parts (ethernet MAC and IP) to match: a packet with the IP
broadcast address should be sent with the ethernet broadcast
address. Win95 barfs. It doesn't seem to be a problem for Win98. (I
would appreciate those with better understanding elaborating.)
The client can specify a preference for a broadcast reply in the DHCP
REQUEST(Win95 doesn't do this). You can force ISC to always broadcast
replys, but I can't quote the specifics (my copy of Lemon & Droms' new
"The DHCP Handbook" is on the bedside table at home).
> From: Nathan Mahon <vaevictus@socket.net>
> Date: Wed, 17 Nov 1999 09:49:06 -0600 (CST)
>
>
> Due to the type of service i'm issuing, our ADSL customers are invoking a
> peculiar situation.
>
> I'm working on getting ISC-DHCP working with our current situation:
>
> 1. all of these accounts are on unregistered ips, NAT translated...
> Each of the different dsl connections connect through a terminator, and
> each should be allowed it's own group (class C worth) of 10.X.X.X
> addresses.
> I've got an Ascend Max Terminator with all the 10.X.X.1 addresses for each
> of the DSL lines, and it does DHCP proxy for all the accounts.
> I've gotten this to work on NT, but you know how we all love NT.
>
> Anyway, I don't know if my configuration is poor or my routing is poor, so
> I'll attach everything below...
> Note: it works locally, notice the 10.0.0.x settings... but won't route
> them through the max terminator.
>
> Please help! :)
>
> vaevictus
>
>
>
> 10.0.0.5 -> local ip of the max terminator
> 10.0.0.2 -> ip of the dhcp server
> 10.0.0.1 -> outside gateway
> 10.0.2.1 -> sample max terminator interface for the dsl
> 10.0.2.2-255 -> ips for that dsl link
>
> Routing tables
> Internet:
> Destination Gateway Flags Refs Use Netif Expire
>
> 10/24 link#2 UC 0 0 xl1
> 10 10.0.0.5 UGSc 0 305 xl1
> 10.0.0.1 0:10:7b:84:bd:9b UHLW 0 104 xl1 1144
> 10.0.0.5 0:c0:7b:84:1f:c0 UHLW 1 0 xl1 619
> 10.0.0.105 0:40:33:5b:11:9 UHLW 1 1301 xl1 585
> 10.0.0.252 link#2 UHLW 2 2 xl1
> 255.255.255.255 ff:ff:ff:ff:ff:ff UHLSb 0 0 xl1
>
> <dhcpd.conf>
>
> option domain-name-servers 216.106.1.2, 216.106.1.3;
> option subnet-mask 255.255.255.0;
> option domain-name "socket.net";
>
> subnet 10.0.0.0 netmask 255.255.255.0
> {
> range 10.0.0.252 10.0.0.253;
> option routers 10.0.0.1;
> option broadcast-address 10.0.0.255;
> default-lease-time 600;
> max-lease-time 7200;
> }
> subnet 10.0.1.0 netmask 255.255.255.0
> {
> range 10.0.1.3 10.0.1.4;
> option routers 10.0.1.1;
> option broadcast-address 10.0.1.255;
> default-lease-time 600;
> max-lease-time 7200;
> }
> subnet 10.0.2.0 netmask 255.255.255.0
> {
> range 10.0.2.3 10.0.2.4;
> option routers 10.0.2.1;
> option broadcast-address 10.0.2.255;
> default-lease-time 600;
> max-lease-time 7200;
> }
>
>
>
>
>
> To Unsubscribe: send mail to majordomo@FreeBSD.org
> with "unsubscribe freebsd-isp" in the body of the message
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-isp" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199911192331.SAA08946>