Loopback

[petros2006]

Hi all
I'm trying to work through an interesting problem.
I have about 150 phones in our company, a mixture of 5215's 5207's and 5205's
The phone network is attached to the data network by a cisco switch which has ip helper services running.
The phones get their ip address from a dhcp server running isc-dhdp-3.03 on a freebsd server on the data side.
The ports where you would plug in either a phone or a computer are at each desk and often, the phone port and data port are side by side.
I notice that if someone accidentally plugs a cable in, one end in a voice port and the other end in a data port,
and then you reboot a phone, the phone will not boot. It stops at the message DHCP OFFER 1Acc on the phone console. If I plug the cable out and reboot the phone, it boots.
Can anyone please tell me why this happens and how to configure things so that the phone will still boot even if someone accidentally does this.
Thanks

 

[Matt85]

the phone and the data(computers) are getting their IP from the same DHCP or is each on seperate on a VLAN or something? It sounds like you have a different range or subnet for you data than the DHCP or maybe they are on a different gateway. If they all have the same subnet and gateway I don't know why it doesn't work when you do that. If you changed the DHCP server for the phones you have to reprogram it in the IP settings form and tell it what the new DHCP server IP is but i don't know what system you have. Give us the IP numbers if you can such as GATEWAY, SUBNET, and IP of the ICP and the Phone. you can check the phone by reading it as it boots up and the computer by going into network connections and double click the Local Area Connection if this is XP then go to the support tab and read off all those numbers.

Matthew McGowan
Reynolds Park

http://www.rpyc.info

 

[MitelInMyBlood]

Sounds like you have physically separate cabling infrastructures for your voice and data networks.
I know some people have dont this although I haven't the foggiest notion why as it seems to defeat the purpose of being able to combine voice & data on one common network and save a lot of infrastructure installation and support costs in the process.
Separate VLANs, yes, but physically separate networks, why?

In such a situation you may have only one alternative and that is to purchase & install "keyed" jacks and change one end of the ethernet cable for the phone to have a keyed plug.
That way the phone (w/keyed plug) can only be plugged into a voice network jack (with keyed receptacle).

Almost idiot-proof, tho the user could still try to plug their PC into a phone jack (but not vice-versa).

Goodness knows there's no shortage of stupid people.
I've even seen network techs cut off the release-pin of RJ45 cables to stop the darn user from unplugging and moving it to a different jack, some people are positively out of control when it comes to "getting on" the network.