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dchp to router behind bridge

Posted: Fri Oct 19, 2018 1:18 pm
by dsalch
I'm having a weird problem with dhcp to a router on a subnet behind a ubiquiti device in bridge mode.

The setup is

Gargoyle router -> ubiquiti radio in bridge mode -> router in dhcp mode

The radio in bridge mode is receiving it's dhcp assignment fine based of it's own mac address.

BUT the router behind the link refuses to take the assigned dhcp ip address, instead it takes a generic pool dhcp address, as if the mac address doesnt match. That's the weird thing, the router is getting assigned a dhcp address, but NOT the one in the dhcp table for it's mac. Yet in the reports for connected wireless hosts, it shows the mac address of the router and it is assigned an ip from the normal dhcp pool.

any ideas?

Re: dchp to router behind bridge

Posted: Fri Oct 19, 2018 3:57 pm
by ispyisail
Subnet problem?

Proably need more information

screen shots, subnets, IP address etc

Re: dchp to router behind bridge

Posted: Thu Jan 03, 2019 3:41 pm
by dsalch
Sorry for the delay, got busy on other projects.

here are a couple of screen shots:
https://drive.google.com/file/d/1YRqY6R ... sp=sharing

https://drive.google.com/file/d/1BN665x ... sp=sharing

Here is the setup:

Gargoyle router at 192.168.3.1

Wireless link at 192.168.3.5 set to bridge mode.
identified as: Mimi-link DC:9F:DB:94:55:5E

Remote router behind the wireless bridge is
LAN 192.168.3.1
WAN should be 192.168.3.99 but picks up 192.168.3.170 from dhcp
WAN is set for dhcp: Mimi-rtr 08:02:8E:DF:0C:F5
WAN is identified by dhcp as : R6120 192.168.3.170 08:02:8E:DF:0C:F5

So as you can see, the remote router is picking up an IP from the general dhcp pool, assigned to the mac of the router but not the IP assigned to that mac.

One other point... the wireless bridge is a ubiquiti link. If i enable their "WDS" mode (full level 2 bridge), the router will not pick up DHCP at all , as if the full bridge mode is not compatible with gargoyle. I have been unable to determine what is the difference between "network bridge mode" and "full wireless bridge" according to ubiquiti.

Re: dchp to router behind bridge

Posted: Mon Jan 14, 2019 2:24 pm
by dsalch
Just checking.. any thoughts?

Re: dchp to router behind bridge

Posted: Mon Jan 14, 2019 4:36 pm
by RomanHK
dsalch wrote:Just checking.. any thoughts?
Hello,
Each interface should have its MAC address, ie.
Wireless Interface (pseudoBridge) DC:9F:DB:94:55:5E - serves as a connection
Physical interface (br0, eth0, ...) 08:02:8E:DF:0C:F5 - serves as packet transfer

This is what I saw with a friend on RouterBoard (RouterOS) and this is not a mistake in Gargoyle.

Correct setup consideration for static DHCP: Mimi-rtr 192.168.3.99 08:02:8E:DF:0C:F5
I still recommend disabling Auto IP Aliasing in UBNT.

Re: dchp to router behind bridge

Posted: Tue Jan 15, 2019 11:49 am
by dsalch
I am confused.. There is a setting in dhcp on gargoyle for each mac address, the link and the router. My difficulty is that the dhcp for the router is not picking up the assigned address, but rather the one from the generic dhcp pool.

What more can i set then the static dhcp assignment?

Mimi-rtr 08:02:8E:DF:0C:F5 192.169.3.99

Re: dchp to router behind bridge

Posted: Tue Jan 15, 2019 4:56 pm
by RomanHK
I did not understand the direction of communication before.
My Theories:

1. Gargoyle router (192.168.3.1, DHCP static reservation Mimi-rtr 08:02:8E:DF:0C:F5 192.169.3.99)

2. UBNT Bridge - Static IP (192.168.3.5, disabling Auto IP Aliasing)

3. Router - DHCP client - here is an important MAC address typing: 08:02:8E:DF:0C:F5 and gets from the 1st Router (Gargoyle) an IP address on the WAN side 192.168.3.99. (I recommend LAN IP address other than IP Gargoyle - eg IP 192.168.5.1

You need to find out what MAC address is on the WAN 3rd Router side.

Re: dchp to router behind bridge

Posted: Wed Jan 16, 2019 4:02 pm
by dsalch
If I follow the question, I can answer that the second router (behind the bridge) does have a different IP address from the first router, on both sides.

here is hte overall layout

WAN 192.168.254.65
gateway router (gargoyle)
LAN 192.168.3.1

192.168.3.5 set by dhcp
ubiquiti Bridge

WAN 192.168.1.99 (supposed to be, but ends up being .170)
router 2
LAN 192.168.1.1

The most curious thing here is that gargoyle is in fact assigning a dhcp to the inside router as it should, but it is assigning out of the generic pool. not the configured dhcp assignment, even though the mac address that shows in gargoyle "connected dhcp hosts) is in fact the one in the dhcp configuration page.

Its not that DHCP isnt working, but that the DHCP is from the generic pool. not the dhcp configuration, even though the mac address is identical in each

Re: dchp to router behind bridge

Posted: Wed Jan 16, 2019 4:53 pm
by RomanHK
It seems to me that the MAC address is already at least twice and therefore there is a collision.

- I recommend restarting routers and seeing who is called R6120.
- If there is still a collision, try to change the MAC address of the WAN port on Router 2, and assign Gargoyle a new MAC correspondent.

Edit:
You can look through SSH on

Code: Select all

/etc/hosts
and

Code: Select all

/etc/ethers
- there are no duplicates or nonsense, can you make a listing of these files and paste them here?

Re: dchp to router behind bridge

Posted: Wed Jan 16, 2019 6:05 pm
by dsalch
here is the contents of those two files:

root@Gargoyle:/etc# cat ethers
88:79:7e:01:3b:88 192.168.3.93
88:79:7e:01:3b:7f 192.168.3.94
90:b1:1c:a4:56:d2 192.168.3.25
00:02:72:75:35:fc 192.168.3.2
44:2c:05:43:61:35 192.168.3.28
08:02:8e:df:0c:f5 192.169.3.99
dc:9f:db:94:55:5e 192.168.3.5
00:1c:10:b1:ee:a8 192.168.3.3
00:0e:c6:00:01:de 192.168.3.9
a0:d3:c1:cf:62:7f 192.168.3.4

root@Gargoyle:/etc# cat hosts
127.0.0.1 localhost
192.168.3.1 Gargoyle
192.168.3.95 DavePhone
192.168.3.94 BrendaPhone
192.168.3.25 OFficePC
192.168.3.9 weather
192.168.3.28 Projector
192.169.3.99 Mimi-rtr
192.168.3.98 Mimi-link
192.169.3.5 Mimi-rtr
192.168.3.5 Mimi-link
192.168.3.2 zoom
192.168.3.3 wetg54g
192.168.3.4 HPPrinterOfficeWire
192.168.3.93 DavePhone
192.168.3.1 Gargoyle # SELF HOSTNAME. DO NOT EDIT OR REMOVE THIS COMMENT!