DHCP hangs up

RouterOS Beginner Basics
1

First of all some explanation.

My network structure looks like this:

Main router: RB411AR (192.168.83.1) connected to the Internet by PPPoE Client via bridged modem.
2 wifi clients connected to it: 192.168.83.2 & 192.168.83.50

Then, from both of these clients (192.168.83.2 and 192.168.83.50) there are networks connected via switches etc. Furthermore, inside there are also APs. Anyway, the whole network gets IPs from DHCP set up on 192.168.83.1 - and in both cases this is the same IP range (192.168.83.0/24). And now, when I’m in house “A” I get the IP (which is listed as static on DHCP lease list) - for example 192.168.83.13. When I simply walk from house “A” to house “B”, I get connected to other wifi network (which uses the same DHCP), I get the same IP of course, but I only can connect to all devices, except 192.168.83.1 and the internet. When I log into RB411AR, it shows “bound”. I have to disable that address and re-enable again. The devices gets the same IP immediately, and teh device gets the access to the internet and to the router. It’s the same story, when I walk back from house “B” to house “A”. What is the problem? How can I fix it? I know, the easiest way would be to set 2 different DHCP servers in each house, but I’d like some devices to have the same IP no matter if they are located in house “A” or for a while in house “B”.

I hope everything what I wrote is clear. :slight_smile:

2

Check the actual dns settings in your computer. If you have win7 it sometimes keeps very old dns settings. I had such problem recently.

3

I’m afraid it’s not the problem. As I wrote, until I login and refresh DHCP for this address it can’t get access to the internet. It happens also on iOS devices (all iPhones and iPads).

4

Are you realy without connection (ping to public ip does not work) or you cannot see the webpages (dns translation does not work)? Have you tried traceroute where the connection ends?

5

I can ping any device in the LAN except the gate 192.168.83.1 - it deoesn’t respond. This is where the traceroute stops. The only thing that helps is to refresh DHCP on router for teh specific IP.

6

Sounds like a gateway problem in the APs. Maybe you should explain what make/model they are, and how they are set up.

7

The gateway is RB411AR with 6.12, but it happened on all previous firmwares too.
I have attached my network structure. The above devices are at house “A” and bottom at house “B”. The problem is when I’m connected to the network at house “A”, walk 50 m to house “B” and connect to network there, I can see every single IP except gateway and what is behind it. When I restart the IP of this device (I have static DHCP configured on the gateway 192.168.83.1) it gets the access to the Internet. The AP’s in both houses are set with DHCP relay to 192.168.83.1.

If you have anything else to ask, please do so, because maybe there are some other important information that I have no idea about.
network diagram.jpg

8

had a similar problemt with win7, since I changed to ubuntu the problems gone. might be a dns issue.
hope that helps

9

Sorry, it doesn’t help. I can’t switch phones to Ubuntu. I have Debian server and few laptops with win7, but I won’t change OS on all devices because of that.

10

can you post DHCP-server settings? Also, what happens if you remove ARP entry for your device?

11

Not sure, if this is what you are asking for…

[admin@MikroTik] > /ip dhcp-server print 
Flags: X - disabled, I - invalid 
 #   NAME                                 INTERFACE                               RELAY           ADDRESS-POOL                               LEASE-TIME ADD-ARP
 0   server1                              wlan1                                                   pool1                                      3d         yes

And the pool…

[admin@MikroTik] > /ip pool print 
 # NAME                                                                                                                         RANGES                         
 0 pool1                                                                                                                        192.168.83.2-192.168.83.150
12

You can check using ‘’/ip dhcp-server export’’ what configuration you have different from the default. Also, seeing export will allow the rest of us just import settings into our own router and see what it does or just see what exactly is set up.

Now, you have set up option that dhcp-server will set up ARP entry. You only need this if you are using arp=reply-only on the interface where dhcp-server resides. If you do not have that, set, you can disable this in server configuration.

13

I finally had a chance to check it out. I disabled ARP on server and it works properly now.
Thanks for your help!