Hello.
Please advise the following question: I have a router Mikrotik it by default gives out dynamic addresses (everything is good), but when the addresses will run out it will be necessary to create a new subnet or it will do it automatically?
New pool won’t be created automatically. So if you expect to have more than around 200 devices in your network, then you have to make subnet larger than /24 … /23 allows for 510 addresses, /22 adds another 512, etc. Increasing subnet requires some dilligence (selecting the right DHCP address range do that it fits the subnet mask, changing subnet mask on a few places, etc.)
Beginners dont normally need more than 50 addresses, is this a real question or a hypothetical?
If its real then you need to provide a far more detailed explanation of your network, the users and services being provided.
I think (guessing, haha I know anav likes this) the question is more this: the user sees that devices always seem to get new addresses, i.e. .254, .253, .252 etc. and what happens when these run out (we reach whatever is the lower limit)
OP needn’t worry. The server will circle around and expired addresses will be reused.
The only scenarios in which this is a problem:
- you just have a lot of devices → increase the available number of IPs.
- you have a place (for example a cafe) where there is a high turnover of people/devices → increase the number of available IPs or make them expire faster. The DHCP server has a value lease time and lowering it makes entries time out faster. I wouldn’t lower it below one hour, because of reasons
, so if there are more than about 100 visitors/devices in an hour, it would be prudent to - again - increase the number of available IPs.
Beginners (with lots of friends) throwing parties like there is no tomorrow? 
Beginners dont normally need more than 50 addresses ..
No they don’t, but do run out of DHCP leases …
- by using large lease times (Many have it on default 24hrs, “no leases available in the afternoon”)
- by having open wifi SSID’s where every iPhone or other smartphone of people passing by will connect on its own
- same thing happens with cars (eg Audi) and trucks passing in your street. (Happened on my city network, with “Free wifi” hotspots)
- with open wifi networks (Typical for Hotspot controlled internet access), it’s not the Internet load, but the DHCP lease address is taken.
So set some simple , well known password on the SSID, or make sure the DHCP lease is dropped on a short idle timeout if no successfull login
(eg Mikrotik Hotspot can do that, AFAIK it works with the “Keepalive timeout” for a new device (host).
Or is it the "Idle Timeout " for a user, as the very confusing documentation says, so I set both to “5:00”, Idle Timeout was not enough.)