Remote DHCP/DNS routing config

[vd123_cisco]

Hi guys,

i am hoping if anyone can reply to my query below.

We have got a new batch of servers and they reside on a separate VLAN 192.168.45.x 255.255.255.0

Those servers are required to be registered on the DNS/DHCP server located on the remote site (SITE 2). Please refer to the attached diagaram. We also have a DHCP/DNS server in our LAN but these new servers will need to be in the domain in SITE 2

Can anyone please guide what are steps required to acheive this. What config would be required on the switch, firewall and the routers.

Thanks

jay

[Reza Sharifi]

Jay,

You DHCP config is correct.  You assigned the IP address of the remote DHCP to SVI/VLAN 45.  Make sure you can ping the remote DHCP server from the switch. If yes, and if the scope is already configured the server should be able to get IPs.

HTH

[vd123_cisco]

Hi Reza,

Thank you for the reply.

These servers wont need the IP addresses from the remote DHCP. I apologise for not clearing this up before.

These servers are currently located on a diffrent subnet(10.10.10.0) and these servers will be migrated in our data centere and these will have a static IP addresses in 192.168.45.0 subnet. These servers will only be communicating with the remote DNS server(10.100.100.150)

I was wondering what config would be required on the firewall and routers.

Do i need to configure DHCP relay on firewall and routers? or just an access-list allowing 192.168.45.0 to 10.100.100.150 on port 53.

Thanks

Jay

[Reza Sharifi · Accepted solution]

Jay,

If the servers are going to be using static IP, then you don't need the IP helper address command you have currently configured for vlan 45. All you need is the SVI with the IP and make sure that the ports connected to servers are also in vlan 45 in you access layer switch. Vlan 45 also needs to be added to the trunk connecting your access switch to the core.

As for DNS, you need to configure the firewall to allow DNS, because DNS servers listen to port 53 (TCP/UDP) and the source port larger then 1023. 

HTH