Tue Jun 8 19:13:58 UTC 2010

Thanks for reply!

I just moved the "subnet 192.168.1.0/24" section out of the "shared
network eth1" and everything works!

Yes you are right. I want to separate devices at layer two. The devices
on the VLAN 101 are actually phones. That's why I set the
default-gateway/router option of this subnet to the IP address of the
core switch (which is layer 3 switch and capable of doing routing).

I guess my problem was on this "shared-network". I will study more on
this. The server was originally set by somebody else. I will try
understand why he was setting it this way, and if there is no good
reason, I will remove them all...

Thanks for help again!

Difan Zhao, M.Eng

Network Engineer

difan.zhao at guest-tek.com

www.guest-tek.com <http://www.guest-tek.com/> 

Office: 403-509-1010 ext 3048

Cell: 403-689-7514

________________________________

From: dhcp-users-bounces+difan.zhao=guest-tek.com at lists.isc.org
[mailto:dhcp-users-bounces+difan.zhao=guest-tek.com at lists.isc.org] On
Behalf Of Randall C Grimshaw
Sent: June-08-10 12:59 PM
To: Users of ISC DHCP
Subject: RE: 

you dont want to define this as a shared network.

On the switch you have also confused the two networks using the
helper-address statement.

if you want these vlans to be separate networks they must remain
separate. (layer 2)

at some point the vlans will connect to a router. (layer 3) on that
router will be a gateway interface. that interface will usually have a
bootphelper statement that forwards broadcast dhcp traffic to the
address of your dhcp server (and back)

Randall Grimshaw rgrimsha at syr.edu

________________________________

From: dhcp-users-bounces+rgrimsha=syr.edu at lists.isc.org
[dhcp-users-bounces+rgrimsha=syr.edu at lists.isc.org] On Behalf Of Difan
Zhao [difan.zhao at guest-tek.com]
Sent: Tuesday, June 08, 2010 1:56 PM
To: dhcp-users at lists.isc.org
Subject: 

Hi experts,

I am trying to provide dynamic IP addresses for devices that are resided
on VLAN 101. The server is currently providing 172.17.x.x/16 range for
its own VLAN 417. My server is RHEL4 running DHCPD version 3.0.1. The
core switch (Cisco 3750) is configured with "ip helper-address
172.17.1.1" on VLAN 101 interface. Here is my dhcpd.conf file:

authoritative;
ddns-update-style ad-hoc;
omapi-port 7911;

shared-network eth1
{
option domain-name "globalsuite.net";
option domain-name-servers 4.2.2.1;
default-lease-time 88200;
max-lease-time 88200;

   subnet 172.17.0.0 netmask 255.255.0.0
   {
       range 172.17.1.10 172.17.199.254;
       option broadcast-address 172.17.255.255;
       option routers 172.17.1.1;
       option subnet-mask 255.255.0.0;
   }

   subnet 192.168.1.0 netmask 255.255.255.0
   {
       range 192.168.1.10 192.168.1.250;
       option broadcast-address 192.168.1.255;
       option routers 192.168.1.254;
       option subnet-mask 255.255.255.0;
   }
}

Here is my eth1:
[root at NE_OVI ~]# ifconfig eth1
eth1 Link encap:Ethernet HWaddr 00:15:C5:F4:CB:22
inet addr:172.17.1.1 Bcast:172.17.255.255 Mask:255.255.0.0

Here is my routing table on the server. The eth0 is WAN interface,
connected with ISP. The eth1 is LAN interface on VLAN 101. The server is
also doing NAT/PAT for the LAN users.

[root at NE_OVI ~]# route -n
Kernel IP routing table
Destination               Gateway                  Genmask
Flags Metric Ref Use           Iface
210.83.99.128          0.0.0.0                    255.255.255.128
U 0 0 0                              eth0
192.168.1.0             172.17.254.1           255.255.255.0          UG
0 0 0                            eth1
0.0.0.0                    210.83.99.129          0.0.0.0
UG 0 0 0                            eth0

Configs on the switch:
!
interface Vlan417
ip address 172.17.254.1 255.255.0.0
no ip route-cache
end
!
interface Vlan101
ip address 192.168.1.254 255.255.255.0
ip helper-address 172.17.1.1
end
!

However my laptop on the VLAN 101 keeps getting IP of 172.17.x.x/16
range... Here is the log.

Jun  8 11:53:47 NE_OVI dhcpd: DHCPDISCOVER from 00:11:43:fe:80:19
(ne-l-d400tester) via 192.168.1.254

Jun  8 11:53:47 NE_OVI dhcpd: DHCPOFFER on 172.17.199.253 to
00:11:43:fe:80:19 (ne-l-d400tester) via 192.168.1.254

Jun  8 11:53:47 NE_OVI dhcpd: if ne-l-d400tester.globalsuite.net IN A
rrset doesn't exist add ne-l-d400tester.globalsuite.net 44100 IN A
172.17.199.253: timed out.

Jun  8 11:53:47 NE_OVI dhcpd: DHCPREQUEST for 172.17.199.253
(172.17.1.1) from 00:11:43:fe:80:19 (ne-l-d400tester) via 192.168.1.254

Jun  8 11:53:47 NE_OVI dhcpd: DHCPACK on 172.17.199.253 to
00:11:43:fe:80:19 (ne-l-d400tester) via 192.168.1.254

Where do I do wrong? How do I fix it?

Thanks!

Difan Zhao, M.Eng
Network Engineer
Guest-Tek Interactive Entertainment Inc. 

www.guest-tek.com

Email: difan.zhao at guest-tek.com
Office: +1 (403) 509 1010 ext 3048
Cell: +1 (403) 689 7514

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