4G with 2.8.0 yields 'CHAT: The modem is not responding to "AT" at MomCmd: labeell.'

mcfly9

Hi,

I have a Sierra Wireless 4G modem that worked perfectly with 2.7.2, but fails with 2.8.0.

Sep 4 15:45:24	ppp	36974	[opt5_link0] Link: reconnection attempt 57912
Sep 4 15:45:37	ppp	36974	[opt5_link0] CHAT: The modem is not responding to "AT" at MomCmd: labeell.
Sep 4 15:45:37	ppp	36974	[opt5_link0] MODEM: chat script failed
Sep 4 15:45:38	ppp	36974	[opt5_link0] Link: DOWN event
Sep 4 15:45:38	ppp	36974	[opt5_link0] LCP: Down event
Sep 4 15:45:38	ppp	36974	[opt5_link0] Link: reconnection attempt 57913 in 2 seconds

Digging a bit on the internet and getting inspiration from opnsense fixes, I was able to get it working by:

editing mpd.script to handle MomIdentGeneriicc (yes, looks like it's mangled) and redirect it to ModemIdentGeneric
power_off then power_on the usb modem in ppp_linkdown using usbconfig

/usr/local/sbin/mpd.script:

MomIdentGeneriicc:
        log "mangled, redirecting"
ModemIdentGeneric:
        set $ModemDescription "Hayes compatible modem"
        if $SimPin != "" call DialPeerSetPin
        if $APN != "" call DialPeerSetAPN
        set $ModemSetupFunc GenericSetup
        return

/usr/local/sbin/ppp_linkdown:

# beginning of the file:
usbconfig -d 8.2 power_off

# normal contents of ppp_linkdown

# end of the file:
( sleep 3; usbconfig -d 8.2 power_on ) &

Having applied these two fixes, it seems to be working ok:

Sep 4 16:16:05	ppp	34413	[opt5_link0] Link: reconnection attempt 8
Sep 4 16:16:06	ppp	34413	[opt5_link0] CHAT: mangled, redirecting
Sep 4 16:16:06	ppp	34413	[opt5_link0] CHAT: +CGDCONT=1,"IP","internet"

I understand that cellular support is pretty poor in FreeBSD, but is there any better way to cope with this issue?

elvisimprsntr

@mcfly9

You have to ask yourself how much is your sanity worth to you?

You will always be better off with an Ethernet connected external cellular modem, which will be completely transparent to pfSense.

Netgear LM1200

mcfly9

@elvisimprsntr yeah, I ask that question myself too... :) I had the modem at hand, and wanted to get use of it without any additional purchase.

mcfly9

Reporting back, it doesn't work. It gets connected, pings go through, but upon more serious data transfer I get socket errors and after a while I get LCP errors and a disconnection.
Frustrating, especially that it worked pretty OK with 2.7.2.
Off to buy a 4G modem with ethernet adapter :)

stephenw10

Hmm, curious it should have worked in 2.7.2. What modem is that exactly?

I have hit that before and handled it by feeding the init string to mpd5 that allows it: &F&C1&D2E0S0=0${temp}

Try that.