Opnsense not receiving updated WAN from modem DHCP

[cduckett]

Had a ton of issues getting Opnsense setup correctly.  Ended up having to spoof the MAC address of a my TP link router to get an accurate WAN IP address.

Still getting intermittent connections that cause Opnsense to drop the WAN connection.  I tried spoofing the MAC address of the Opnsense computer for a laptop that I connected directly to the modem and that worked briefly as well.

My current setup is as follows:

1. Opnsense computer - connected to port 1 of TP link managed switch
2. Motorola MB8600 cable modem - connected to port 2 of TP link managed switch
3. TP Link Archer C7 w/ OpenWRT firmware (setup as a dumb AP) - connected on port 2 of port 3 of TP link managed switch
4. TP link TL-SG108E managed switch - used this tutorial to setup VLANs Link

I have Opnsense logs and screenshots if that will help deduce what I can do to fix this issue.

[priller]

Remove VLAN 1 from Port 2.  The port to the cable modem needs to be isolated.

A cable modem will only provide an address to the first MAC it sees.  Since you have a managed switch, it can be seeing the MAC of the switch management IP first  So, if the TP-Link works as I expect it to, removing VLAN 1 from the CM port will make the problem go away.  Make the change and reboot everything.

EDIT:  Also, remove the spoofing.

[cduckett]

Remove VLAN 1 from Port 2.  The port to the cable modem needs to be isolated.

I thought the port for the modem needed to be connected to the same VLAN as the Opnsense computer.

My setup looks like the following:

A cable modem will only provide an address to the first MAC it sees.  Since you have a managed switch, it can be seeing the MAC of the switch management IP first.

This is what I thought the problem might be.

[priller]

The graphic looks right, but the details in the tutorial are wrong.  The tutorial shows all ports also living in VLAN 1 (attached graphic).  That needs to be stripped out of Port 2.

You have already seen the impact of that error by making it work (for a while) by cloning the TP's MAC.  That ain't right, having the same MAC on two device in the same VLAN will always present "random" problems.

[cduckett]

The graphic looks right, but the details in the tutorial are wrong.  The tutorial shows all ports also living in VLAN 1 (attached graphic).  That needs to be stripped out of Port 2.

Ok, I removed Port 2 from VLAN 1 as seen below.  I've also attached graphic of the PVID settings to make sure these are correct as well.

Assuming that these are both correct, I should be able to power cycle my modem and make sure that the Opnsense computer is receiving a WAN IP address from the CM, correct?

[priller]

Sounds like a plan!       To keep it clean, remove the spoofing config on the OPNsense WAN.

[cduckett]

Well my system has been running fairly well so far; only one random disconnection but I was able to release/renew DHCP and get back up and running.

Thanks again for your help!

[priller]

Well my system has been running fairly well so far; only one random disconnection but I was able to release/renew DHCP and get back up and running.

Thanks again for your help!

Excellent! Happy it's working.

[cduckett]

So I had an extended power outage and when everything powered back on, I ran into the same issue with Opnsense not able to get a DHCP offer from the modem/ISP.  Not sure what to do now.  I can attach my system log but it wasn't able to resolve the WAN IP until I spoofed my Opnsense router MAC onto my laptop, connected to the CM, and then connected Opnsense computer to CM.

Code: [Select]

2021-05-17T18:11:45 dhclient[78122] No DHCPOFFERS received.
2021-05-17T18:11:28 dhclient[78122] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 17
2021-05-17T18:11:14 dhclient[78122] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 14
2021-05-17T18:11:01 dhclient[78122] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 13
2021-05-17T18:10:54 dhclient[78122] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 7
2021-05-17T18:10:51 dhclient[78122] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 3
2021-05-17T18:10:49 dhclient[78122] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 2
2021-05-17T18:10:48 dhclient[78122] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 1
2021-05-17T18:10:48 dhclient[78122] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 1
2021-05-17T18:10:48 dhclient[8012] Starting delete_old_states()
2021-05-17T18:10:48 dhclient[39362] Removing states through old gateway '192.168.100.1' (new gateway '')
2021-05-17T18:10:48 dhclient[12880] Comparing Routers: Old: 192.168.100.1 New:
My CM IP is 192.168.100.1; I've tried refusing leases from that IP but it didn't correct the issue.

Code: [Select]

2021-05-17T18:18:46 dhclient[52446] No DHCPOFFERS received.
2021-05-17T18:18:42 dhclient[52446] DHCPOFFER from 192.168.100.1 rejected.
2021-05-17T18:18:42 dhclient[52446] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 4
2021-05-17T18:18:30 dhclient[52446] DHCPOFFER from 192.168.100.1 rejected.
2021-05-17T18:18:30 dhclient[52446] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 12
2021-05-17T18:18:28 opnsense[63780] /widgets/widgets/dyn_dns_status.widget.php: Aborted IPv4 detection: no address for em0_vlan99
2021-05-17T18:18:17 opnsense[29828] /widgets/widgets/dyn_dns_status.widget.php: Aborted IPv4 detection: no address for em0_vlan99
2021-05-17T18:18:15 dhclient[52446] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 15
2021-05-17T18:18:01 dhclient[52446] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 14
2021-05-17T18:17:51 dhclient[52446] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 10
2021-05-17T18:17:47 dhclient[52446] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 4
2021-05-17T18:17:45 dhclient[52446] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 2
This is the log after I spoofed the Opnsense computer MAC on my laptop.

Code: [Select]

2021-05-17T18:27:20 dhclient[52446] DHCPACK from 98.XXX.XXX.XXX
2021-05-17T18:27:20 dhclient[52446] DHCPREQUEST on em0_vlan99 to 255.255.255.255 port 67
2021-05-17T18:27:18 dhclient[52446] DHCPOFFER from 98.XXX.XXX.XXX
2021-05-17T18:27:18 dhclient[52446] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 16
2021-05-17T18:27:03 dhclient[52446] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 15
2021-05-17T18:26:56 dhclient[52446] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 7
2021-05-17T18:26:49 dhclient[52446] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 7
2021-05-17T18:26:44 dhclient[52446] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 5
2021-05-17T18:26:41 dhclient[52446] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 3
2021-05-17T18:26:39 dhclient[52446] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 2
2021-05-17T18:26:37 dhclient[52446] DHCPDISCOVER on em0_vlan99 to 255.255.255.255 port 67 interval 2