We have this setup currently - internet into Cisco PIX firewall. From the PIX to an HP switch, the UC520 is also connected to the HP switch (the UC also has our Cisco IP phones and PC's attached in its switch ports). We now have an ESW520 switch that I want to use to replace the HP switch. Initially I connected the LAN interface of the PIX into the switch (tried the uplink port and a regular switch port), connected the expansion port of the UC to the uplink port of the ESW and connected a PC to the ESW. No internet access. I can ping both the PIX and the switch from the PC but no internet. I've also tried PIX out to the WAN port of the UC, then to the ESW, also no internet.
I'm really at a loss here...I'm just not sure how to get this configuration to work and am getting very frustrated! I'd appreciate any help that can be offered and will gladly provide whatever details are needed. Thanks.