Connect 2 Data Devices & Phone to 1 Port

[jameshwylie]

I have a UC540 connected to a ESW520 24 Port POE with SPA504G phones.

I have connected a small 5 port switch to the PC connector on the back of the phone.  I then have a PC and a Network printer connected to the 5 port switch.  Under this configuration I am having trouble with the PC being able to renew its IP Address.  I am using DHCP on my Windows server for IP address distribution.

How can I fix this problem and do I need to change a setting for the port on the Cisco 24 Port Switch?

[Steven Smith]

You should look at the security settings under the switchport.  If you are going to allow more than 3 mac addresses behind the switch, you should change the setting to the amount of devices are you going to allow.  But, the reason you are having the problem is port security.

http://www.cisco.com/en/US/docs/switches/lan/csbms/esw500/administration/guide/ESW_500_Administration_Guide.pdf

Port security starts at page 141 of this guide.

Also, connecting multiple devices behind a phone switchport is not supported.