Not getting DHCP lease from Netgear LB1120 LTE Modem Bridged

[mrn]

I'm attempting to use the LB1120 to provide backup WAN access.

I am looking to pass through the WAN IP via bridge mode to the pfSense router.

It's configured to get a DHCP address but the LB1120 is not providing one.

If I connect a laptop to the modem, even through pass-through, the laptop is able to get a dhcp lease and a public ip. pfSense is not able to receive one.

Here's the associated log for this issue:

Mar 23 21:42:27	dhclient	51291	No DHCPOFFERS received.
Mar 23 21:42:17	dhclient	51291	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 10
Mar 23 21:42:07	dhclient	51291	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 10
Mar 23 21:42:00	dhclient	51291	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 7
Mar 23 21:41:47	dhclient	51291	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 13
Mar 23 21:41:38	dhclient	51291	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 9
Mar 23 21:41:31	dhclient	51291	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 7
Mar 23 21:41:26	dhclient	51291	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 5

Any hints for how to get this to work?

I already tried to set this in the Options modifiers for this interface, based on some other forum posts I found elsewhere, without any luck:

supersede subnet-mask 255.255.255.0

[chpalmer]

@mrn try rebooting the modem. each time you change what you have plugged in to the modem you must reboot it due to the fact that it will lock on the first Mac address it encounters during that boot.

[mrn]

@chpalmer Thanks for the tip. I did restart when I was doing my testing. Just in case I tried to restarting again.

I rebooted the modem and then I also rebooted pfsense.

I tried with the special options modifier, and I also tried it without the options modifier.

Mar 24 16:53:32	dhclient	83583	exiting.
Mar 24 16:53:32	dhclient	83583	connection closed
Mar 24 16:53:32	dhclient	52303	FAIL
Mar 24 16:53:32	dhclient	83583	No working leases in persistent database - sleeping.
Mar 24 16:53:32	dhclient	83583	No DHCPOFFERS received.
Mar 24 16:53:25	dhclient	83583	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 7
Mar 24 16:53:08	dhclient	83583	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 17
Mar 24 16:52:58	dhclient	83583	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 10
Mar 24 16:52:43	dhclient	83583	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 15
Mar 24 16:52:36	dhclient	83583	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 7
Mar 24 16:52:31	dhclient	83583	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 5
Mar 24 16:52:31	dhclient	83583	igb3 link state down -> up
Mar 24 16:52:30	dhclient	83583	send_packet: Network is down
Mar 24 16:52:30	dhclient	83583	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 14
Mar 24 16:52:16	dhclient	83583	send_packet: Network is down
Mar 24 16:52:16	dhclient	83583	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 14
Mar 24 16:52:10	dhclient	83583	send_packet: Network is down
Mar 24 16:52:10	dhclient	83583	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 6
Mar 24 16:52:08	dhclient	83583	igb3 link state up -> down
Mar 24 16:52:07	dhclient	83583	DHCPDISCOVER on igb3 to 255.255.255.255 port 67 interval 3
Mar 24 16:52:07	dhclient	84336	PREINIT
Mar 24 16:51:37	dhclient	72973	exiting.
Mar 24 16:51:37	dhclient	72973	connection closed
Mar 24 16:51:36	dhclient	72973	igb3 link state up -> down

Same issue both ways.

[michmoor]

@mrn Have you tried plugging your laptop/desktop directly into the modems ethernet (WAN) port to see if you pick up an IP address?

[chpalmer]

@mrn ^^ what Michmoor said above!

I use this same modem with Verizon and have good luck with it other than being in a poor bandwidth area.. cameras still upload to the cloud so I am happy.

But I am in bridge mode without any extra settings.

[mrn]

@michmoor Yes it does! This is why it's driving me a but nutty.

[mrn]

@chpalmer I wonder what I'm doing wrong...I don't even know what else to look at at this time. I guess I should post my configs soon, just in case I'm missing something obvious.

[chpalmer]

@mrn can you show a screenshot of your modem interface WAN page?

Assuming you are absolutely not getting an IP? Not just a connectivity problem?

[chpalmer]

Also.. look up the MTU for the carrier you are using.. Verizon is 1400. Wont affect the DHCP but will affect traffic.

[mrn]

@chpalmer

Here's my pfsense interface:

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Here's my LTE modem configuration (I didn't see any other sections of importance):

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As you can see from the following image, my laptop got the bridged IP address correctly. Oddly enough, I didn't have to reboot the LTE modem to get this IP.... I wonder if it's permanently tied to my laptop MAC address even through reboots? That doesn't seem right.

login-to-view

[mrn]

It's not the cable either. I just used the same cable for the router and laptop.

[michmoor]

@mrn that’s a weird one. I would look into that system logs to see what’s going on (dhclient) with DHCP.

[mrn]

@michmoor I already did that in my first post, unless you mean some other place.

[michmoor]

@mrn yes i see that i apologize.
This doesnt seem like a pfsense related issue.
DHCP is 4 message types
Discover
Offer
Request
Acknowledgement

pfSense is sending out a broadcast looking for a dhcp server. The dhcp server (cable modem) will hear that broadcast and respond with an offer (public IP from the pool).
From your system log messages (assuming no filtering of the log messages), pfsense is looking for the dhcp server and its not responding.
As mentioned it could be a sticky mac address issue where the first record mac learned on the cable modem port is what will get the IP address and subsequent macs get nothing. If so and if rebooting the modem doesnt clear the mac then i would contact the service provider.

edit: Why are you hard coding a mac address in the pfsense WAN DHCP settings?

[mrn]

@michmoor

The reason I hardcoded it is that I have an high availability setup. Right now the LTE modem is connected to my secondary pfsense, but I want to me able to move the connection to the primary if necessary. I know that having the same MAC address can make it a seamless transition.

[mrn]

It won't pull an neither on bridged NOR on router mode.

[mrn]

@mrn And yes, I have updated it to the latest firmware version.

[michmoor]

@mrn in Router mode i suspect the cable modem is giving out a DHCP address in the RFC1918 space which based on your screenshot, pfsense will ignore. Uncheck that option and test again.

[mrn]

@michmoor Believe it or not, it STILL doesn't pull a DHCP lease.

I'm about to return this thing and try something else.

[chpalmer]

@mrn uncheck the two boxes for the reserved addresses on your WAN page.