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Date:      Tue, 18 Mar 1997 19:24:56 +0100 (MET)
From:      Josef Belkovics <belkovic@albert.osu.cz>
To:        George Uhl <guhl@mitre.org>
Cc:        freebsd-bugs@freebsd.org
Subject:   Re: ISC dhcpd
Message-ID:  <Pine.BSF.3.91.970318172220.534A-100000@albert.osu.cz>
In-Reply-To: <v02130500af54019a679f@[128.29.114.90]>

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> >I need install DHCP server (ISC dhcpd). Does FreeBSD IP stack allow the
> >all-ones broadcast to go out onto the lan unchanged?
> No.
> >Or FreeBSD changes
> >the all-ones broadcast into the local subnet broadcast (e. g.
> >255.255.255.255 -> 193.84.224.255 etc.).
> Yes.

> I did a dhcp implementaion that used a raw IP socket, but first
> I had to constuct the UDP and IP header information.  I did use
> 255.255.255.255 as the destination address. I configured the
> routing table with a static route {host 255.255.255.255 gateway
> albert}, but I only configured one interface on the host.

ISC dhcpd on FreeBSD needs bpf (berkeley packet filter). For each
interface one device /dev/bpf?. 

> Since it sounds like you are configuring multiple interfaces on a
> host, this becomes harder.  What is the correct IP address for a
> given interface if you don't know what subnet it is attached to?
> I don't want to make suggestions (or guesses) without knowing
> more about your network topology.

My topology is:
ep0 net 193.84.224.0 mask 255.255.255.0
#p1 net 193.84.226.0 mask 255.255.255.0	in future
#p2 net 193.84.227.0 mask 255.255.255.0	in future
ep3 net 193.84.228.0 mask 255.255.255.0

My opinion arised from text 'README' in port 'DHCPD-BETA-5.14.tar.gz'.
Author indirect says that FreeBSD hasn't an ip stack that allows the
all-ones broadcast. (You say it also.) As a result (says author) my
clients will not see DHCPOFFER. 

But dhcpd logs that at least some clients received (c)dhcpdiscover -
(s)DHCPOFFER - (c)dhcprequest - (s)DHCPAK etc. If client requests that
server respond using unicast, all is good. But if client requests that
server respond using broadcast, then I may have problem. With single
interface I can solve one by creating martian route. My question is, what
to do with dhcpd on multiple interfaces with condition 'client requests
broadcast'? (I don't know, if win3.x (+ tcp/ip), win95 or nt clients
request sometimes broadcast.)

> >If yes, which file from the kernel source I must 'rewrite'. Or exists
> >another way how can I cancel (i know better word) a bit too clever ms-dhcp
> >clients? I can't use static routes "static { host 255.255.255.255 gateway
> >albert };" in /etc/gated.conf, because I have several network interfaces.
> 
> George Uhl
> email: <guhl@mitre.org>
> phone: 703-883-7305
> 
> The MITRE Corporation
> 1820 Dolley Madison Blvd.
> McLean, VA. 22102

JPB



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