Mikrotik ip addresses

Question

In order to expand available pool of IP addresses assigned via DHCP, I have followed an advice to simply change the 192.168.1.1/24 to 192.168.1.1/21. Having around 126 PCs @ school and some 200-300 student portable devices, I'm still having the issue of "Limited access", which is usually solved by assigning a static IP address.

If changing the range by simply adding a /21 doesn't solve the pool of available IP addresses, would you suggest setting a separate interface? Let's say 192.168.1.2?

p.s. I see a lot of manuals describing things done via Mikrotik terminal, which I tend to do in Mikrotik visual interface (IP -> Addresses). Thanks for any help in advance.

you understand that 192.168.1.1/24 is greater than 192.168.1.1/21? — Iłya Bursov, Apr 17 '15 at 22:10
/21 is more than enough for that number of users. Make sure that you change the dhcp scope not just the subnet mask on the interface. — pajaja, Apr 18 '15 at 01:09
@Lashane, it's the other way around. /21 has 11 bits for the subnet instead of only 8 for /24. — Brian White, Apr 18 '15 at 01:38
This question belongs on [Network Engineering](http://networkengineering.stackexchange.com/), not here. — Dessa Simpson, Mar 20 '17 at 02:24

score 2 · Answer 1 · answered Apr 19 '15 at 13:42

Ensure all points are well conifgured:

Address configuration from router. As you say IP > ADDRESSES -> 192.168.1.1/21 assigned to correct interface
Mikrotik DHCP SERVER. IP > DHCP SERVER > NETWORKS, ensure Address: 192.1.68.1.0/21 Gateway: 192.168.1.1 (is it?) and DNS SERVERS ( like 8.8.8.8 8.8.4.4) IP > DHCP SERVER > DHCP ensure correct interface and correct pool
Ensure Pool configured : IP > POOL Set addresses to 192.168.1.2-192.168.7.254

Remember:

IP addresses from hosts will remain unchanged while Lease time isn't completed (by default 3 days)
You can analize the behaviour of leases in IP > DHCP SERVER > LEASES. Tell us what you see, and don't forget to see mikrotik log and verify hosts auto-configuration ( important GATEWAY config from hosts)

score 0 · Answer 2 · answered Feb 26 '16 at 06:14

If it shows "Limited Access" probably the gateway cannot communicate with extended IPs; Check the "netmask" to be set /21 in here: IP -> DHCP Server Networks tab.

Also, you can add another pool of IPs on same interface.
By using the feature of "Next Pool" in IP -> Pool after setting the first pool for example "pool1" with range of "192.168.1.1-192.168.1.254" you can set the field Next Pool to "pool2";
hence the Dhcp Server would go for next pool automatily.
(Ofcourse you should define pool2 with range you want, like: "192.168.2.1-192.168.3.254" )
In both cases remember to

check the gateway netmask to support all IP ranges.
And the firewall rules like NAT table, if there are any.

score 0 · Answer 3 · edited Jan 13 '17 at 10:11

0

it will not work. IP range 192.168.0* can be extended to include 192.168.1* and 192.168.2*. if you extend 192.168.1* to 192.168.2*, it will not work. try reconfiguring your pool to the 192.168.0* range. then extend it to 192.168.1* or .2* range. otherwise change the net mask.

edited Jan 13 '17 at 10:11

FelixSFD

6,052
10
43
117

answered Jan 13 '17 at 10:10

Cephas

1

score -1 · Answer 4 · answered Apr 18 '15 at 01:37

-1

I assume you meant "192.168.2.*" insead of "192.168.1.2". You need to understand that the dotted-quad notation of 4 octets is only a convenience notation. IP4 is a pure 32-bit number so "/21" means the most-significant 21 bits are the "network address" and the remaining 11 bits (32-21) are the "subnet address". 2^11 == 2048 so you can support over 2000 devices on that subnet.

If it's not working, it's problems with your DHCP server or the physical network not being able to handle so many devices.

Check your DHCP configuration to make sure it can assign all those addresses. Many systems have settings of "first address" and "allowed devices" which would, for example, be 192.168.1.40 and 2000 leaving the 1-39 available for static configuration.

answered Apr 18 '15 at 01:37

Brian White

8,332
2
43
67

Yes, Brian I meant 192.168.2.* Was writing the initial post when I was about to faint and knock out to sleep. You know, that fuzzy condition before sleep. Something tells me, it's not good to do tech things while being in such a condition. – user72160 Apr 19 '15 at 09:46
1

I figured out, it's not only the IP addresses tab and DHCP tab that I needed to play with, but in one youtube video (https://www.youtube.com/watch?v=konrWKhbIr0) at 1:13 the video jumps to Pool tab. In my pool tab, the addresses ranged only from 192.168.1.2 - 192.168.1.240. Perhaps, that's what accounted for this. I changed it to 192.168.1.2 - 192.168.4.240. Will see what happens. I should say, Mikrotik is a bit different from what I have encountered: TP-Link, Zyxel, Linksys. It's more complex. To my mind, they could have put Pool tab into DHCP tab. – user72160 Apr 19 '15 at 09:56

Mikrotik ip addresses

4 Answers4