Hello, I will upgrade the asa 5510 from 256 MB RAM to 512 MB RAM. But I have read that some asa5510 firewalls have 1 slot and others 4 slots for RAM. How can I find out without open the case how many slots are available?
There are very few ASAs that were shipped with 4 slots, so you probably have 1 slot on your ASA.
If you still have 4 then install your memory to the slot that has the memory in it already, if you are replacing memory cards.
If you are adding a second 256 memory, make sure you install it to the second in a row after the one that is there already.
I hope it is clear now.