Hi, a little question.
How many firewall entries can RB450G handle without any problems? I mean, it is possible to import for example like 1.000.000.000 IPs and drop all incomming packets from these address?
Thanks for answer.
Re: How many entries in FW can RB450G handle?
Sure everything is possible, but don't expect your routerboard to route stuff faster than ISDN speeds with 1 billion rules 
Assuming all that stuff fits in flash and ram ...
Assuming all that stuff fits in flash and ram ...
Re: How many entries in FW can RB450G handle?
At this time, I have a 500 rules fw listing (including, mangle and nat) with no problems on a unique internet gateway.
I could easily reach 1500 rules with more complex scenarios than I have now (adding hotspot facility, ppp's, more internet gateways, more local areas), but I could not imagine, where a 1b rules could be used to.
I believe that you have reached wrong solution for your problem (if it is a problem and not just a question).
Answering to your question, I cannot answer but there is a limit. CPU (on lots of packets) is the cause of increment on latency. As a result of low resources you will encounter packet loss.
Try to search for iptables limits, since mikrotik firewall is actually that.
I could easily reach 1500 rules with more complex scenarios than I have now (adding hotspot facility, ppp's, more internet gateways, more local areas), but I could not imagine, where a 1b rules could be used to.
I believe that you have reached wrong solution for your problem (if it is a problem and not just a question).
Answering to your question, I cannot answer but there is a limit. CPU (on lots of packets) is the cause of increment on latency. As a result of low resources you will encounter packet loss.
Try to search for iptables limits, since mikrotik firewall is actually that.