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My Network Setup consist of two Routers, one LTE Router (Router 1) working as a Gateway to the Internet, the other one (Router 2) working as Access Point in order to expand the network accessibility.
In addition, a RPi Zero running Pi.Hole acts as the DHCP Server of the Network.
Problem:
Within my network Setup, devices that connect via Router 2 don't get the correct IP assigned by the DHCP Server (DHCP Range: 192.168.1.100 - 192.168.1.250) but end up with 169.....s . Devices that connect via Router 1 get corrects IPs.
This Problem started when I introduced Pi.Hole as DHCP Server. Before that, Router 1 was acting as DHCP Server and every device got a correct IP. I can reach devices with wrong IPs via ssh and those devices even use Pi.Hole as Ad-Sinkhole but fail to communicate with its DHCP Server.
I'd appreciate every hint on why this is not working and if there's a possibility to get this to work.
Setup:
Router 1:
- Model: Huawei E5186s-22a.
- Firmware: 21.306.01.07.22 (Standard Huawei Firmware)
- IP: 192.168.1.1
- DHCP is deactivated.
- This Router establishes the connection to the internet.
Router 2:
- Model: Linksys WRT54GS Version 6
- Firmware: DD-WRT v3.0-r40559 micro (08/06/19)
- IP: 192.168.1.2
- Subnet Mask: 255.255.255.0
- Gateway: 192.168.1.1
- Local DNS: 192.168.1.1
- DHCP is deactivated.
- This router works as AP and has been configured according to this Guide (Normal Version (Same Subnet))
Router 1 and Router 2 share one Wireless SSID but work on different channels.
DHCP Server:
- Model: RPi Zero with PiHole installed
- IP: 192.168.1.10
- DHCP enabled:
- DHCP Range: 192.168.1.100 - 192.168.1.250
Wiring:
- There's a wired ethernet connection between Router 1 and Router 2.
- There's a wired ethernet connection between Router 1 and the DHCP Server.
- The DHCP Server connects to LAN 1 of Router 1.
- LAN 2 of Router 1 connects to LAN 1 of Router 2.
Attempts so far:
- Activating DHCP forwarding from the Router 2 to the DHCP Server --> No visible effect.
- Setting the DHCP (192.168.1.10) server as local DNS on Router 2 --> Router 2 shows in the Pi.Hole's Log as Device . Beside that nothing changed.
- Plugging the DHCP Server into the Router 2 --> Problem stays but now device connected to Router 1 end up with a wrong IP. Devices connected to the Router 2 get the correct IPs.
- Connecting LAN 2 on Router 1 to the Internet Port on Router 2 but that did not change anything apparent.
- I tried changing the wiring so that the DHCP connects to LAN 2 of Router 1 and LAN 1 of Router 1 connects to LAN 1 of Router 2. --> again no change
I`ve been running wireshark to look for DHCP requests.
Here's a device that ended up with a wrong IP trying to get something from the DHCP Server:
Number Time Source Destination Protocol Length Info
1108 133.580324 0.0.0.0 255.255.255.255 DHCP 378 DHCP Discover - Transaction ID 0x47de264f
1079 115.557997 0.0.0.0 255.255.255.255 DHCP 392 DHCP Discover - Transaction ID 0x46df78a0
I could not find any other log from this device with another DHCP message than DHCP Discover.
Peter S
Posted 2020-01-31T15:55:15.980
Reputation: 101
1Does the RPi receive DHCP "discover" packets from clients? Does it send out offers in response? And does it receive the actual "requests" after that? – user1686 – 2020-01-31T16:18:29.093
Yes, Devices that connect via Router 1 get corrects IPs --> I just realised that I failed to mention this in my post and added this. – Peter S – 2020-01-31T16:26:55.710
Right, but I'm specifically asking about the devices which don't work... – user1686 – 2020-01-31T16:37:02.397
OK I did not get that. I'm not quite sure how I can monitore that but it seems like a good idea to get into that. Any advice on a monitoring tool? – Peter S – 2020-01-31T16:39:57.333
I added two lines from a wireshark log – Peter S – 2020-01-31T18:37:45.670