08-19-2006 03:49 AM - edited 03-03-2019 04:35 AM
We are configuring DHCP server on our L3 switches / Routers in our network. network range is in subnet 255.255.252.0.
Sometimes it is observed that the pc s get the ip address from dhcp server but the subnet mask is 255.0.0.0 instead of 255.255.252.0.
Kindly help me in understanding as to why the client subnet mask is 255.0.0.0,
08-19-2006 04:00 AM
hi abhay,
will you please post your configuration?
regards
Devang
08-19-2006 04:19 AM
ip dhcp database ftp://user:password@172.16.4.253/router-dhcp write-delay 120
ip dhcp excluded-address 172.16.1.100 172.16.1.103
ip dhcp excluded-address 172.16.2.100 172.16.2.103
!
ip dhcp pool 0
network 172.16.0.0 /16
domain-name cisco.com
dns-server 172.16.1.102 172.16.2.102
netbios-name-server 172.16.1.103 172.16.2.103
netbios-node-type h-node
so make sure you have configure right subnetmask
rate this post if it helps
regards
Devang
08-20-2006 03:19 AM
Pls find my dhcp configuration
ip dhcp pool PKT
network 10.2.188.0 255.255.252.0
default-router 10.2.188.1
netbios-node-type m-node
dns-server 10.2.188.9
Eventhough the subnet mask is 255.255.252.0 the client takes the ip address but subnetmask as 255.0.0.0.
08-20-2006 02:37 PM
Configuration looks fine.
Try capturing the output from the following the commands whilst doing a dhcp renew.
debug ip dhcp server events
debug ip dhcp server packets
08-20-2006 03:18 PM
Verify that you have "IP CLASSLESS" in your configuration.
For most version of IOS it's on by default, but it's worth checking anyway.
Good Luck
Scott
08-20-2006 06:59 PM
Hi,
The router is assigning the natural mask to the clients because it probably ignores the subnet mask you have configured.
Can you make sure there's a space between the IP address and subnet mask in the network statement. You might even want to remove the network statement and reconfigure it.
Hope that helps!
Regards,
Sundar
08-20-2006 07:24 PM
Agreed w/ Scott that the ip classless may be an issue. Moreover, remember to include the "ip dhcp excluded-address " to exclude the gateway & any issue that was statically assigned to the host.
If it still not solve the problem, please post full config and also try to use prefix as below :
ip dhcp pool PKT
network 10.2.188.0 /22
Hope this helps.
08-21-2006 04:50 AM
Thanks for the suggestion,
Will check and revert on this.
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