Strange Configuration, Please help me

RouterOS General
1

Hi everybody!
I’m connected to a new ISP.The details for the configuration they gave me are as further:
IP: xx.xx.xxx.154/32
Subnet:255.255.255.240
Gateway:xx.xx.xxx.81

I tried to configure on IP addresses but I don’t know which IP to use for Network and Broadcast.
When I configured these IP on windows the internet works, but through mikrotik no.
Is it any possibility to find Network and Broadcast IP while using the configuration on windows?

I would appreciate very much your help.

Many blessings

2

Try to find out from this site http://www.subnet-calculator.com/

3

If subnet is 255.255.255.240
then in mikrotik you should add address xx.xx.xx.154/28, routeros will calculate network and broadcast automatically.

4

net = xval
32 = 1
31 = 2
30 = 4
29 = 8
28 = 16
27 = 32
26 = 64
25 = 128
24 = 256


take 255 xor (xval - 1)
so for 30 ==> 255 xor (4 - 1) = 255 xor 3 = 252
so for 28 ==> 255 xor (16 - 1) = 255 xor 15 = 240

5

Yes I tried with xx.xx.xx.154/28, and on IP routes I put xx.xx.xx.81 as given by ISP. Mikrotik calculates the network and broadcast automatically but the internet doesn’t work.
In this configuration I opened “new terminal” and tried pinging the gateway or DNS.
The message that appeared was “no route to host”.
With the same configuration in windows it works. Is it any command or way to find network and broadcast IP while it is working on windows?

I’m thinking if I might know the exact network and broadcast IP I can put them manually while on IP address I put xx.xx.xx.154/32

6

no route to host means that you have to add default gateway:
/ip route add gateway=xx.xx.xx.81

7

Yes of course I puted the gateway, but still doesn’t work.
The ISP is applying MAC address filtering, but in this case I’m using the same network card.
No doubt about that.

8

imho. if you have gateway (lets say x.y.z.81 and network mask is 255.255.255.240 you cannot have ip address x.y.z.154

because x.y.z.81 with network mask mentioned above is for network x.y.z.80 with broadcast address x.y.z.95

maybe i am wrong - i am open for suggestions

9

Correct - 255.255.255.240 → 11111111.11111111.11111111.11111000 → /28

if you have x.x.x.154/28

Network/first address is:x.x.x.144
Broadcast/last address is: x.x.x.159

Gateway must be from the range of x.x.x.145 - x.x.x.158, but you have x.x.x.81

10

It is the reason why you can not tourch the gateway.

Ask your ISP to check it for you.