We are having issues with our phones not pulling down DHCP info. My question is this. On a single campus network (all behind one router), do i need the ip helper-address command. If so, do I apply it on the sub-interface of the router, or the virtual interface of the switch, or both. Also, does my switch need a virtual interface at all.
The DHCP pool is located on the GW router.
If I manually configure the IP information on the phone, it will come up. I then can go back to DHCP and the phone works fine.
Helper is only required if your DHCP server is not in same vlan as the end devices are.If you have DHCP set on a Cisco IOS router or switch that is directly connected to the end devices or if the DHCP server (MS,third party etc), then you dont need helper.
In your case its the latter. Is the router act like a "router on a stick" config ? How many sub ints do you have ? Do you have a DHCP pool configured for each sub interface/subnet?
That's what I was thinking. That's why it's so confusing. I do have multiple subinterfaces, but i am only doing DHCP for the one VoIP network. I posted a modified config below of what I have on the router.
description ***Primary VoIP Interface***
encapsulation dot1Q 3
ip address 192.168.123.1 255.255.255.0
ip broadcast-address 192.1168.123.255
no snmp trap link-status
h323-gateway voip interface
h323-gateway voip bind srcaddr 192.168.123.1
no ip dhcp use vrf connected
ip dhcp excluded-address 192.168.123.1
ip dhcp pool VoIP
network 192.168.123.0 255.255.255.0
option 150 ip 192.168.123.1
For the switch, I have no virtual interface referencing the VoIP network. I do have the VLAN and the switchport voice command under the interface where the phone resides.
okay. i got it to work by going ahead and inserting the ip helper-address. i wanted to try that first, because i didn't want to risk the debug bringing down the router and/or switch. i figured the ip helper-address couldn't harm anything.
all and all, i still can't understand why i needed to put it in. however, it is working right now. i will investigate it further, because it is really going to bug me.
The short answer is that you don't.... That isn't entirely true while at
the same time it kind of is, but for the most part you don't configure
the softkeys. You enable or disable them via TCL. Here is the long
answer. Be sure to read the whole thing or e...
Topology: IP Phone > Switches > Microsoft NPS setup to forward 802.1x
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