A bit confused

NetGuruSomeDay

Hi Senior engineers,

I'm a junior who needs some help.

We have mostly switches in our network with a firewall. All IP are provided by the firewall through NAT.

Now the issue is we have Voip phones connected to a third party switch none Cisco that functions as DHCP for the phones in a different office. I will like to remove the 3rd party switch and have the Cisco distribution switch function as the DHCP. Any idea how to achieve this?

I'm struggling quite a bit as this 3rd party device is often unstable and has been causing a lot of issues.

my idea was to add the DHCP scope to the VoIP vlan as IP helper address.

I'm fairly new to this so please have some patience

tomtom1

A layer 2 switch can't provide DHCP as far as I know. You need some kind of router for this (the default gateway of the VOIP segment for example). That router can either do the DHCP request itself or forward the DHCP related traffic to another DHCP server on the netwerk, via the ip helper command.

You configure an ip-helper on the interface level using the ip helper-address ​command.

NetGuruSomeDay

Hi Thom,

Thanks for your reply.

So basically i can setup up a vlan on the firewall and add the subnet address to it or add a voip interface to the distribution switch with ip helper-address command?

tomtom1

NetGuruSomeDay wrote: »

Hi Thom,

Thanks for your reply.

So basically i can setup up a vlan on the firewall and add the subnet address to it or add a voip interface to the distribution switch with ip helper-address command?

I'm assuming the VoIP VLAN already has an interface address somewhere in the network, for it to be routed to the rest of the network? Or is the switch that is currently in place Layer3 capable?

NetGuruSomeDay

Currently the only thing the switch is providing is DHCP and is connected to our distribution switch, all our phones are connected to our access switches and to our workstations. De 3rd party switch is only providing IP to the phones.

tomtom1

NetGuruSomeDay wrote: »

Currently the only thing the switch is providing is DHCP and is connected to our distribution switch, all our phones are connected to our access switches and to our workstations. De 3rd party switch is only providing IP to the phones.

And what does the 3rd party switch hand out as the default gateway for the VOIP scope?

NetGuruSomeDay

Its a dead default gateway so the Vlan has not internet connectivity. Is that what you are asking?

English is not my first language.

chmod

Can you upload a diagram? that would make it easier for us.