DHCP and 2 subnets
Chris Arnold
carnold at electrichendrix.com
Mon Apr 7 02:33:40 UTC 2008
On Sunday 06 April 2008 06:42:51 pm Simon Hobson wrote:
> Yes, that looks OK, but you can make life easier for yourself with
> some formatting ;-) Also, you can move common options (like the lease
> times) to the global scope. So you could end up with :
Done
> That sounds pretty standard. What is logged when a 192.168.123.x
> client gets the wrong address ? Also, it may be worth using a sniffer
> (like wireshark) to see what packets are being passed on the networks
> concerned.
This gets logged to the dhcp server:
Apr 6 22:12:51 mail dhcpd: DHCPDISCOVER from 00:0b:db:c8:f1:71 (Izabella) via
eth1
Apr 6 22:12:51 mail dhcpd: DHCPDISCOVER from 00:0b:db:c8:f1:71 (Izabella) via
192.168.123.2
Apr 6 22:12:51 mail dhcpd: DHCPREQUEST for 192.168.124.144 (192.168.124.1)
from 00:0b:db:c8:f1:71 (Izabella) via 192.168.123.2: ignored (not
authoritative).
Apr 6 22:12:51 mail dhcpd: ICMP Echo reply while lease 192.168.124.144 valid.
Apr 6 22:12:51 mail dhcpd: Abandoning IP address 192.168.124.144: pinged
before offer
Apr 6 22:12:52 mail dhcpd: DHCPOFFER on 192.168.123.253 to 00:0b:db:c8:f1:71
(Izabella) via 192.168.123.2
This seemed to me to "cached" somewhere so i restarted and this restart is the
above log.
Also, i have configured dhcp relay on 1 of our windoze servers that is on
192.168.123 network. Nothing gets logged at that server and when i had the
router configured for dhcp relay, nothing got logged at that device either.
This is logged at the 192.168.123.x client on a reboot:
Apr 6 22:12:13 Izabella ifup-dhcp: eth0 (DHCP)
Apr 6 22:12:13 Izabella ifup-dhcp: .
Apr 6 22:12:13 Izabella kernel: NET: Registered protocol family 17
Apr 6 22:12:14 Izabella ifup-dhcp: .
Apr 6 22:12:14 Izabella kernel: e1000: eth0: e1000_watchdog_task: NIC Link is
Up 100 Mbps Full Duplex, Flow Control: RX
Apr 6 22:12:14 Izabella kernel: ADDRCONF(NETDEV_CHANGE): eth0: link becomes
ready
Apr 6 22:12:15 Izabella ifup-dhcp: .
Apr 6 22:12:19 Izabella syslog-ng[2019]: last message repeated 2 times
Apr 6 22:12:19 Izabella ifup-dhcp: no IP address yet... backgrounding.
Apr 6 22:12:53 Izabella ifup: eth0 device: Intel Corporation 82540EM
Gigabit Ethernet Controller (rev 02)
Apr 6 22:19:21 Izabella ifprobe: eth0 changed config file:
ifcfg-eth0 --> restart interface!
Apr 6 22:19:21 Izabella ifdown: eth0 device: Intel Corporation
82540EM Gigabit Ethernet Controller (rev 02)
Apr 6 22:19:21 Izabella dhcpcd[4929]: terminating on signal 15
> I don't understand what you mean by : "I have the router config set
> to point to the gateway of the 192.168.123.x network"
>
>
> But from the description, the Netscreen DHCP Relay agent sound normal.
On the router in the dhcp relay option there is a place to provide an ip
address. I assume this will need to be pointed to the dhcp server. In the
above statement, i had it pointed to the gateway of the 192.168.123 network
which, i believe is not right. So i changed it to point to the dhcp server. I
will try to attach a screen shot to this email. Thanks again for all your
help.
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