[binaryturtle]

If they are behind a NAT/ stateful firewall there is just so much connections it will handle at once. I think OpenWRT has like 16K max by default, f.ex. So for less than 16K requests by different users/IPs… each is kept for about 1 minute I think… it quickly will go down, I guess. :)

cat /proc/sys/net/netfilter/nf_conntrack_max

Should give some details.

[201984]

Do you know if using the DMZ feature on most routers instead of port forwarding would get around this limit, or if there's any other way?

[binaryturtle]

With OpenWRT we can increase the limit, if needed. But it's a delicate process you need to balance out carefully depending on your router. I doubled my slots and it works fine:

It's done via /etc/sysctl.conf

> net.netfilter.nf_conntrack_max=32768

Afterwards "sysctl -p" to apply/ reload the config file. But increasing blindly is a bad idea… it needs to be done with ip_conntrack_buckets in sync for proper balance (memory use, CPU usage). Best to read upon it.

But just going from 16K to 32K shouldn't be any problem for most routers these days.