Recently installed an ASA5505 for a client. They have Verizon DSL (7mb down, 384up package). So my config is Verizon (Westell) DSL modem connected to e0/0 (VLAN2) of ASA. From there I have e0/1 (VLAN1) connected to a 3COM 2250 Plus 50 port switch.
Since installing the ASA client has been complaining of a major slow down in Internet speed. Contacted ISP and they had me remove the firewall from the equation and hook modem directly to laptop. With this setup I get between 6-7mb download speeds. When I put the ASA back into the mix though, the speed drops significantly. The speed will varry but 90% of the time they do not even get 1mb download speeds.
The configuration is pretty straight forward, not doing a whole lot with the box other then using it for VPN (IPSEC).
I'd really like some suggestions or ideas on what could be causing this or even where to start looking as I am not sure.