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dhcp

Hello friends,,


My scenario is this

i have two domains(old and new).as of now iam in process of transferring all roles and data to the new domain. all r fine ok...good

but the problem i face is with dhcp.i exported the conf of dhcp from old server and put it on a win 2003 server in the new domain.i assigned the new gateway & new dhcp and changed the dns domain name on the dhcp in new server.i authorize the new dhcp server and unauthorised the old one...but the clients are not getting ip address from the new dhcp server .....

OK tried a lot of things

This is my situation now friends

The wireless clients are getting IP from the new dhcp server

Ip details for wireless network

10.2.32.1 to 10.2.32.254

subnet mask is 255.255.255.0

Default gateway in the new dhcp is 10.2.32.21

Dns is 10.2.32.20

As for the Lan Clients they are not getting IP from the new DHCP Server

IP details for lan clients:

10.2.34.1 to 10.2.34.254

subnet 255.255.255.0

gateway in the new dhcp is 10.2.32.21

dns is 10.2.32.20

Even when i assign static ip i get a message showing,the default gateway is not on the same segment that is defined by the ip address and the subnet mask.do you want to save this configuration??

After that i get a warning also



Now i figured out something...

The dhcp works with the old DNS(10.2.32.11) address when i assign static ip on clients even if the gateway is 10.2.32.21(tmg),and they are able to access internet

But when i change the DNS to new server(10.2.32.20) the clients are not able to connect.....

please help me guys..

thanks in advance
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riazambalath
Asked:
riazambalath
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2 Solutions
 
Chris MillardCommented:
Try changing the Subnet Mask of the LAN DHCP Scope to 255.255.0.0 and see if that works?
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Chris MillardCommented:
You are getting the DHCP configuration warning/error message because the default gateway is indeed on a different subnet to the IP address scope. If any PCs DID get an IP address from that LAN scope, they would not be able to contact the default gateway, and subsequently would not be able to contact the DNS server, and therefore would not get internet connectivity.
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OsmozeCommented:
try to move also client from 10.2.34.1 to 10.2.34.254 to 10.2.32.1 to 10.2.32.254 or change the mask to 255.255.0.0 without that they cannot communicate ,because they ar not on the same subnet .

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Chris MillardCommented:
Also, if you want to narrow the subnet down, you could change it to 255.255.252.0 - this would allow both DHCP scopes to access all IP addresses between 10.2.32.1 - 10.2.35.254
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riazambalathAuthor Commented:
iam having the vlan information saved in my core switch(catalyst 4506)...does changing the dhcp result in conflict???
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OsmozeCommented:
If you have inter VLAN routing enabled somewhere (in the core switch / router ) and DHCP vlan can communicate with Client Vlan ,it will not confilict , just rectify the addresses assigned to clients or change the mask .
if theres no intervlan routing ,and the DHCP is on a differents VLAN from Clients  they cannot see each other
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riazambalathAuthor Commented:
i do have all vlan information configure on a core switch.....the mask in core switch is 255.255.255.0.

if i change the mask in dhcp...does it create any conflicts??
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Chris MillardCommented:
no - it shouldn't...
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riazambalathAuthor Commented:
the current vlans are

10.2.10.0
10.2.20.0
10.2.30.0
10.2.32.0
10.2.34.0
10.2.40.0
10.2.50.0
10.2.60.0
10.2.70.0
10.2.80.0
10.2.90.0
10.2.100.0
10.2.110.0
10.2.120.0
10.2.130.0
10.2.140.0

all using subnet mask of 255.255.255.0

so i have to recreate the vlan and assign 255.255.252.0 as the mask????
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OsmozeCommented:
no , just move the DHCP server from VLAN  10.2.32.0 to 10.2.34.0 or all clients from 10.2.34.0 to VLAN  10.2.32 .0 , no need for mask changing if so .

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riazambalathAuthor Commented:
Actually i have to keep the VLAN'S,it is an instruction from the headquarters.....
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OsmozeCommented:
Let's explain this ,

When a machine startup in a LAN ( or VLAN) it sends brodcasts paquets  looking for DHCP server that may be on the LAN so it can get a valid IP addres for communicating with other machine on that LAN (Vlan) .
broadcast paquets are not routed , so the requests for IP address will not reach any DHCP server on a differents LAN ( VLAN ) ,Except when there's a DHCP rely on the machines LAN and can forward the requests to the DHCP server ( he already knows - configured  where is the DHCP sever is located ) .

refere to :
http://technet.microsoft.com/en-us/library/cc756865(WS.10).aspx

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riazambalathAuthor Commented:
Everything seems ok now..the clients are getting the IP from the new dhcp server.....

Wireless clients have access to internet and is working

The lan clients, it shows local and internet,bu there is an exclamation mark and it says unathenticated and is not able to access the internet
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OsmozeCommented:
Unauthenticated mark on the LAN icon means that you have a NAC on your network  and you need to setup 802.1X  and authenticate on the radius /AD server to be able to connect . now i guess you re connected to a guest LAN .
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