I am new to this forum so I am not quite sure where to post this.
My house network consists of 5 AP (RB941,RB952,RB52G) managed via Capsman from RB750GL (7.1.3v on all). Internet connection goes to RB750GL from an ISP fibre modem. The adress pool is default (192.168.88.10..254) with several fixed IP assigned (the APs have a fixed assignments on 192.168.88.2-9). DNS of the ISP is set on the RB750GL.
Following some reboots there is a problem with internet access on my Samsung android phones and PCs - even though the IP look properly assigned the phones indicate that there is no internet connection. I have to set in the phones static IPs in order to make them work. I would prefer the DHCP to manage the pool to avoid duplication conflicts.
I have tried to factory reset everything several times and set config again from the beginning but after some time the problem occurs again.
Any suggestions appreciated. I am a newbie with mikrotik so please be gentle 
.
Please /export hide-sensitive the Router configuration…
Guessing you’re using the default config. You might want to check in IP>DHCP Server>Network and make sure the 192.168.88.0 “DHCP Network” has a “Netmask” set. In some version, this isn’t set automatically, and some DHCP clients expect it. The “Netmask” value should be “24” for the defaults.
Otherwise, yeah a config to look at be helpful.
Hi. How do I export the config hiding the sensitive data? Sorry - like I said newbie 
OK - see config attached. Changed the Netmask to 24
config.rsc (10.6 KB)
Maybe someone else see something, but that pretty standard.
You can enable more logging on the DHCP server, to see what might be different from a request from a Samsung vs your other clients.
You can do this by using this at the Terminal:
/system/logging/add topics=dhcp
Then in winbox app or their admin web pages (“webfig”), you can go to “Log” which will start to show more information about the specifics of each DHCP request. Hopefully, turning the Wi-Fi on/off on the Samsung shows up in the Mikrotik logs & you can compare what happens with doing same Wi-Fi on/off that does work.
You can remove the extra loging by going to System>Logging and remove the item with “dhcp” as the “Topic” in winbox or webfig. Or, the following command will also remove the logging added above:
/system/logging/remove [find topics~"dhcp" action=memory]
The only problem I’ve seen is if the netmask isn’t set, a few devices have trouble getting an IP from DHCP in the past. But changing that has always fix it in my case. You’re using 7.1.3 which should have a working DHCP Server, especially with what looks like the default configuration…but V7 is also pretty new.
You could perhaps try to use the test version 7.2rc4 to see if that fixes your Samsung device issue too, but maybe someone spots something that’s wrong in your config…
I’m hoping the logging shows something “different” between a working request and non-working request.
From a quick look i can’t see anything wrong in the configuration…
From what you describe in your first post, the devices get an IP address from the DHCP server successfully, but they can not reach the internet…
I would suggest you change the default network to something else, lets say 192.168.1.0/24 and then make sure the devices are getting an IP from the correct DHCP server…
This is known to be problematic at times, unpredictable suggest just disable for now
/interface detect-internet
set detect-interface-list=all internet-interface-list=all lan-interface-list=
LAN wan-interface-list=WAN
Other than that not too much I can see. I am not a fan of capsman for anything less than four devices,
but in any case not sure if Capsman replaces putting WLANs as bridge ports??
/interface bridge port
add bridge=bridge comment=defconf interface=ether2
add bridge=bridge comment=defconf interface=ether3
add bridge=bridge comment=defconf interface=ether4
add bridge=bridge comment=defconf interface=ether5
add bridge=bridge interface=WLANX… ???
OK. I got a sort of a workaround by assigning in winbox for each of the ~40 devices MAC’s fixed addresses via DHCP Server/Leases => Make static. So for now the devices connect with DHCP rather quickly and. It is as if the DHCP server had a problem with assigning addresses on its own - without a “map”.
One thing I am wondering also - is RB750GL “powerful enough” for my 40 device network? Perhaps a router with a newer faster chip would manage better? So far it was working fine but as the network is expanding maybe an upgrade is in order?
I also have this problem 20 days pased i trying to solve but i couldn’t! When a pc internet connection down i checked it had gotten correct ip,dns but internet dose not work.when i write arp -a on computer cmd it show me a fake mac address for lcal gateway .please help