ip helper-address

Chriskoh · ‎10-06-2019

Hi

Could anyone let me know whether each vlan can define 2 ip helper-address ? Example below which i have this existing vlan in Switch:-

interface Vlan100

ip address 172.30.49.254 255.255.254.0

ip helper-address 172.30.48.5

no ip redirects

ntp broadcast

As above, i would like to split 2 scopes from Dhcp windows server

- from 172.30.48.1 to 172.30.48.254 ( For data)

- from 172.30.49.1 to 172.30.49.253 (For voice media with DHCP scope options include dscp values )

If i configure the switch port as below, will those voice medias (hard phones) automatically receive ip from dhcp windows service from scope range 72.30.49.1 to 172.30.49.253 ?

- interface gig1/0/20

switchport access vlan 100

switchport mode access

switchport voice vlan 100

mls trust qos dscp

spanning-tree portfast

Please enlighten me .. Thanks in advance

luis_cordova · ‎10-06-2019

HI @Chriskoh

As far as I know, the data vlan should not be the same as the voice vlan

It should be something like that:

interface Vlan100 (data)

ip address 172.30.48.254 255.255.254.0

in this case, the server (172.30.48.5) is within the same broadcast domain, so the ip helper-address command is not necessary

interface Vlan110 (voice)

ip address 172.30.50.254 255.255.254.0

ip helper-address 172.30.48.5 <-- DHCP server

- interface gig1/0/20

switchport access vlan 100

switchport mode access

switchport voice vlan 110

On the DHCP server you must create two scopes, one for data and one for voice

Regards