DHCP client discovering too many interfaces
I just noticed something weird on my firewall Linux box (Debian
GNU/Linux 2.2 standard, plus security.debian.org fixes).
This box has 3 interfaces: lo of course, plus eth0 which is hooked to my
cablemodem (an external interface) and eth1 which is hooked to my
internal LAN. Obviously eth1 has a static IP address; my cable company
wants me to use DHCP to discover the IP address for eth0, although I've
had the same one since installation on June 1.
Up until Sep. 9, it all worked fine and I'd see DHCPREQUEST notices in
my daemon.log every 30 minutes or whatever the default was, and no other
DHCP activity to speak of.
On Sep 9 I apparently installed a new security fix for dhcp-client, and
it restarted. Ever since that moment, I've had DHCPDISCOVER requests
for both my lo and eth1 interfaces logged to daemon.log every few
seconds, per interface!
Sep 9 10:54:54 homegw dhclient-2.2.x: DHCPDISCOVER on lo to 255.255.255.255 port 67 interval 8
Sep 9 10:54:56 homegw dhclient-2.2.x: DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 17
Sep 9 10:55:01 homegw dhclient-2.2.x: DHCPDISCOVER on lo to 255.255.255.255 port 67 interval 19
Sep 9 10:55:13 homegw dhclient-2.2.x: DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 11
Sep 9 10:55:20 homegw dhclient-2.2.x: DHCPDISCOVER on lo to 255.255.255.255 port 67 interval 16
Sep 9 10:55:24 homegw dhclient-2.2.x: DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 17
...
Then every 6 minutes or so I'll see this, which I didn't used to get
before, either:
Sep 24 00:46:27 homegw dhclient-2.2.x: No DHCPOFFERS received.
Sep 24 00:46:27 homegw dhclient-2.2.x: No working leases in persistent database - sleeping.
Sep 24 00:46:27 homegw dhclient-2.2.x: No DHCPOFFERS received.
Sep 24 00:46:27 homegw dhclient-2.2.x: No working leases in persistent database - sleeping.
Things still _appear_ to be working OK, but my log files are getting
absolutely enormous with all this extra stuff. And it seems like
unnecessary work on the part of my firewall system. And maybe even
extra traffic on my local LAN?
I see (in the man page for dhcp-client) where I specify what interfaces
dhcp-client should attempt to manage on the command line, but that would
involve changing the /etc/init.d script, which I'm loathe to do since it
would mean maintaining that through package updates, etc.
Isn't there some kind of configuration option I can specify in
dhclient.conf to tell dhcp-client to manage eth0 only, and ignore all
other interfaces? I tried the dhclient.conf man page but couldn't
really come up with the proper syntax. There doesn't seem to be
anything relevant in the DHCP mini-HOWTO, there're no docs to speak of
in the ISC page, and I can't get to www.debian.org to check the mailing
list archives :-/.
Also, does anyone have any idea why this suddenly started happening when
I updated DHCP? I've since rebooted and still see this. Or, was it
always doing this but not logging it before?
--
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Paul D. Smith <psmith@baynetworks.com> Network Management Development
"Please remain calm...I may be mad, but I am a professional." --Mad Scientist
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These are my opinions---Nortel Networks takes no responsibility for them.
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