I have a Cisco ASA 5510 that I'm having throughput problems with. I can't seem to get more than about 13MBps throughput from the inside <-> outside or inside <-> dmz (I have not tried dmz <-> outside.) All interfaces are hard coded to speed 100 / duplex full; the devices on either side of the firewall are Cisco devices (a 3550 that is our Internet router) with a hard coded 100 / full applied to the interface facing the firewall, and on the inside I have a 3560 with a hard coded 100 / full applied to the interface facing the firewall. Neither the 3550 or the 3560 are showing errors on the interfaces facing the firewall. In short - I don't think this is a speed/duplex issue.
I have replaced the wiring to no avail. I am running the latest switch IOS on both the 3560 and the 3550, and 8.2(4) on the ASA. All devices have been rebooted (and we've had this issue for a while, but now that I have a 75MBps circuit to the 3550, I'd like to get more than 13MBps through the firewall.) The speed is being tested with speedtest.net as well as a speed testing system provided by the ISP; if I plug a laptop into another port on the 3550 and configure it correctly, I get a speed rating of about 70MBps.
The firewall is on a VLAN that has only it and the interface on the 3560 switch. I believe this is a variation of the recommended method of connecting the firewall to the network (rather than having it on a network with other devices.)
Let me be clear - it works - it's just very slow in comparison to what I expect.