From: David Presotto <presotto@closedmind.org>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] my cpu-in-vmware problem: it's weird :-)
Date: Wed, 23 Apr 2003 08:52:48 -0400 [thread overview]
Message-ID: <bab9cae1b867e48e342f9c93748cf6e9@plan9.bell-labs.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0304222130190.26835-100000@maxroach.lanl.gov>
Doing a ping before giving out an address is a suggestion from
an RFC, don't remember which. It solves a world of problems;
systems that have grabbed an unused address without using dhcp,
dhcp servers that have lost their database, systems that overrun
their lease (lots of these amongst dumb clients)...
Our dhcpd does it too. If we don't have a
static binding for a system AND the system has never gotten a
dhcp address from us before we look for the oldest (we think unused)
binding and then do a quick ping to make sure it really is unused.
If noone answers the ping, we hand the address out.
Vmware is being reasonable there.
The random
06:34:12.096343 0:50:56:cc:31:ba Broadcast ip 590: 172.16.189.254.bootpc >
255.255.255.255.bootps: xid:0x7a2b9449 secs:8 C:172.16.189.254 file
""[|bootp]
packet that you see might be 172.16.189.254 sending a dhcp request
to refresh its dhcp lease. Are you giving our really short leases?
I don't know the output of tcpdump that well. Having a client address
(C:172.16.189.254) in a request is a sure sign of a renewal. However,
there should also be DHCP options in the packet. Does tcpdump not
print them?
next prev parent reply other threads:[~2003-04-23 12:52 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-23 3:49 ron minnich
2003-04-23 12:52 ` David Presotto [this message]
2003-04-23 17:08 ` Micah Stetson
2003-04-23 17:20 ` David Presotto
2003-04-30 0:24 ` Boyd Roberts
2003-04-30 0:26 ` Boyd Roberts
2003-04-23 15:12 ` Russ Cox
2003-04-23 16:11 ` ron minnich
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