This is fine for homelab firewall or even production firewall for very small network,I would boost the memory to 32,these model can go up to 32 MB of RAM, you may want to upgrade the code to the latest code 6.x train which is 6.3.5 code, with the current code you cannot do 802.1q trunking, with 6.3.5 your maximun interfaces will be 4, two physical and two virtual interfaces.
The 501 are EOSales but still used and good for learning.
Now If you have money you can get the asa5505 with Sec plus license to learn the 7.x,8.0 code, PIX501 cdoes not support any other codes beyond 6.3.5, but again pix501 is t
here is a link with some geting stared with pix code 6.3
The current code will provide you with the basics firewall functionality, inside interface for your private LAN and outside interface for the public network, to upgrade the code you will need access to the cisco software download library but this is only for folks that have some type of service contract which will give you access to code upgrades and Cisco TAC support as well, now you may say " I don't need service contract" but this is the way it works, you may contact TAC directly to see if you can get other options to obtain that code.
You can still work with 6.3.1 code and practice with this code, you still have the two inside/outside interfaces. Just that the benefit of 6.3.5 code will give you the extra two virtual or VLAN interfaces to practice with if you want to have two different private networks.
Also , here is a good interactive link learn about the newer firewall models and its components , you may be able to access the link with your guess account.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...