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IP phones are getting wrong IP addresses - Packet Tracer

Level 1
Level 1

Hi, I'm new at Packet Tracer. I'm supposed to create a scenario with six IP phones. I've configured a VoIP server on a router that also provides DHCP service just for the phones. However, the phones that are connected to a PC are getting IP addresses from the pool of VLAN 2 (which is the VLAN for data) instead of VLAN 1 (which is the VLAN for voice). The interfaces on switches are configured for both Data and Voice but the server is still assigning the wrong IPs and the phones are not getting their line numbers. I also have to mention that IP phones that are not connected to PCs do get the right IP addresses (Phone0 at Multilayer Switch, for example). I attach the .pkt file (avaliable for PT 8.1.1) and a picture of the topology. If you need more information about the scenario please let me know.





2 Replies 2

Martin L

this could be issue with PT and DHCP.  not sure if u can use router as dhcp and server at the same time.

then, in real gear, voice vlan in switchport command has more options; 4, I think. PT does not have that.

You could use dhcp pool on server for voice traffic.

Also,  I would not use vlan 1, try different vlan id.  that vlan is security risk and should be avoided all times.


you can find some samples that come with PT for voice and dhcp. check them out to see how dhcp is set up to be used by phones.


Regards, ML
**Please Rate All Helpful Responses **

Hey there. I took a look at your file. It seems things are basically fine. The phones look like they grabbed addresses from your vlan 2 pool possibly before you got vlan 1 routed properly? I'm not sure, but they aren't giving up their vlan 2 addresses. If you were to delete a phone and re-add a new one you'll see that the new device should get an IP from your vlan 1 DHCP pool. This was my experience when going though your topology. I deleted the ext 1100 phone and when I re-added it I connected to gig 1/3 on the switch. You'll need to add in the data vlan for the PC behind the phone to get a proper address also. 

I stopped troubleshooting after that. The phone didn't register, but your question was about the incorrect IP addresses so I figured you may enjoy finding out why the phone didn't come up. Hopefully this helps you.