I currently Have a 10Mbit Full duplex circuit connected to a small unmanaged switch which then connects to a Sonicwall Firewall / Router. I have several public IP addresses (/28) that are assigned to several devices in my setup. Now the problem is the small switch I have was lent to me and needs to be returned, I have replaced this switch with several other switches but for some reason any other switch I use causes the network to become extremely slow. I believe this is a problem with the autonegotiation of theses hubs, so I am thinking of purchasing a small managed switch (cisco 300 series) and making the receiving port on the swith Explicitly 10Mbit Full Duplex and see if this works.

My question is, being that this is a managed switch and needs an IP, will I still be able to run my public ips through it? Say the circuit has 70.80.4.1 - 7 will I still be able to assign 70.80.4.2 to my firewall and 70.80.4.3 to my router connected to some other port in the switch? Will I have to assign the switch a public IP address in this range as well for it to "route" to those other devices or does the switch does not care what IPs goes through it while operating as a Layer 2 Switch?

Any help would be greatly appreciated. Thanks in advanced!