DNS and DHCP issue with two different IP Addresse range

Question

Hi,

I have a question about DHCP. We have two different IP Address Range on our DHCP Server.

192.168.1.0 IP Address Range, that is for wired LAN

and

172.30.0.0 IP Address Range and that are for WLAN

The problem is the users is getting both IP Address one for LAN from 192. and one from WLAN 172.

My problem is when I ping the client machine, I get the answer from 172.30.0.0 IP Address Range or I cannot ping. Because the both Ip-Address is record on the DNS server 192.168. and 172.30 for example for machine namded "zert734". If I try to ping "zert734". I get no answer. Is there any way to get if I ping the client machine, I get the answer from 192.168.1.0?
At the time I am going to the DNS server and delete the IP-Address 172.30.0 and run flushdns, and then I can ping the machine name ****"zert734".

I know it DNS issue.

Regards

Nick

Answer 1

Hi Candy,

Thanks for your replay. I am not sure what you mean. But I dont have two different locations. Both IP-Range are on the same location.
We only have two different IP-Address.
I have read the Link you provide me. It mean I have to create new subnet / Scope and DNS Policy?
Do you know a guide Link for step by step?

Regards

Answer 2

Hi Candy,
Thanks again for your replay.

We have two IP Address Range on the DHCP Server.

1) 172.30.0.2 subnet 255.255.0.0 and 192.168.1.2 subnet 255.255.255.0

We use the IP Address 172.30. Range for LAN and WLAN and the IP Address 192.168. for LAN.

If for example the host machine "zert734"(it is Noetbook) use WLAN, get the IP from 172.30. and when use the LAN, get IP Address from 192.168.
So both IP Address is now recorded on the DNS server.

I try now to ping the host machine "zert734" I get no answer, until I go to DNS server and delete "zert734" with IP Address 172.30 and clear cashe, then I can ping the "zert734" and I get a answer from IP Address 192.168.

Hope you understand now my issue.
Regards

Nick

Answer 3

Hi Candy,

Ok I will post you some screenshots. I can maybe clear more details. The user get from a reservation IP from DHCP for LAN from 192.168. If the user switch on the WLAN, he gets an IP Address from 172.30. Then the both IP address for example 172.30.0.39 and 192. 168.1.22 are now in DNS record.

Now if I ping the machine name, I get Reply from 192.168.1.22: Destination host unreachable.
If I delete the IP address 172.30.0.39 from DNS server and clear the cache and run ipconfig / flushdns , I get a response, Reply from 192.168.1.22
Hope that help you

Regards
Nick

Answer 4

Hi Nick,

Let's clarify again. Which subnet did you ping the client machine from? 172.30 subnet or 192.168 subnet or non of them?

If you are in 172.30 subnet and then ping the machine name, you will always get an IP address from 172.30.

If you are in a different subnet from 172.30 subnet and 192.168 subnet. When you ping the machine name, with DNS round robin, sometimes, you will get reply from 172.30 subnet and sometimes you will get reply from 192.168 subnet.

At this time, it depends on whether you can communicate with the 192.168.1.22 IP address. If you cannot ping 192.168.1.22 then you will get Destination host unreachable.

If you want to check DNS resolution, you can just use nslookup.

Best regards,

Candy

Answer 5

Hi Candy,

I ONLY Ping the machine name and not any subnet. Because I dont know in which subnet user is.
Again for clairfy. I pin only the machine name and it does not answer, if the user are or were in 172.30 subnet and 192.168.

If I delete on the DNS server the entry 172.30 for the machine, I can ping the machine name and I get answer from 192.168 subnet.

Hope that is clear now

Regards

Nick