[SOLVED!] Losing constant Internet connection on Mofi 4500 (and my mind)

Related to Router Devices ONLY
Forum rules
Use the SEARCH function for related issues PRIOR to posting for assistance.
afroken3130
Posts: 6
Joined: Wed Oct 14, 2020 10:08 am
Has thanked: 0
Been thanked: 0

Re: [SOLVED!] Losing constant Internet connection on Mofi 4500 (and my mind)

Post by afroken3130 » Thu Oct 15, 2020 1:44 pm

patchesj wrote:
Wed Oct 14, 2020 4:11 pm
Do you have IPv6 enabled? I recently did some testing with IPv6 and found some odd behavior that I would say was very similar to a state table filling up. e.g. new connections would fail, existing or established would continue to work, etc. I went back to IPv4 only and the mofi seems to be much happier....
I have IPv6 disabled on the MOFI and on my router. I have also tried disabling DHCP on the MOFI, but the behavior is the same whether off or on.

The behavior has definitely changed as of the last week or so. Before when the connection would drop, the internet light on the MOFI would not be solid and I would have to restart the MOFI to even access it. Now when the connection drops, the lights on the MOFI are normal (at least when I look at them after I notice no internet) and I can still access it. However, I just have to reboot the router to get connectivity back. Behavior is the same with multiple routers. I can also no longer reliably connect to any VPN services on any protocols either through my router or through the MOFI.

I have no idea what is up with VPN connectivity, but I think the router issue may be a matter of the MOFI temporarily dropping the external IP and the router not being able to do a hot refresh.

different
Posts: 1
Joined: Thu Oct 15, 2020 8:26 pm
Has thanked: 0
Been thanked: 1 time

Re: [SOLVED!] Losing constant Internet connection on Mofi 4500 (and my mind)

Post by different » Thu Oct 15, 2020 8:33 pm

I recently ran into this thread and finally dig some digging since it was driving me crazy. There are likely two issues going on here, and while I don't know the answer to the true question "why is this happening" I was able to fix the latter of "why doesn't this recover". Warning, this gets a bit technical.

Basically, there is a script on the system located on `/usr/sbin/gobi-retry.sh` - this script is in charge of checking the health of the device, etc. Now, since my device would "partially" lose internet, basically some DNS issues it seemed, I chose for my device to do the "alternate ping check" which the UI states will do DNS. Under the hood it does a DNS lookup and a curl.

If you ssh to the device and call for logs via `logread`, you'll probably see something stating "Something is wrong with HTTP connections" if your situation is similar to me. There is a bug in the retry script which if it gets a DNS connection but NOT the HTTP one, it thinks everything is fine. This, for me, obviously was not fine.

The important part of the script looks like this;

Code: Select all

	if [ "$CHECK1" = "0" ] || [ "$CHECK2" = "0" ]; then
		#we have internet so lets remove the reboot counter
		rm -rf /tmp/greboot.stage1
		rm -rf /tmp/gobi-reboot.log
		uci -q set luci.main.gobi_reset=0 && uci commit luci
		echo 0
		return 0
	fi
Since `$CHECK1` passed but `$CHECK2` doesn't, it just jumped into the loop. My gut says this is a bug/oversight. So I changed it to the following;

Code: Select all

	if [[ "$CHECK1" = "0" && "$CHECK2" = "0" ]]; then
		#we have internet so lets remove the reboot counter
		rm -rf /tmp/greboot.stage1
		rm -rf /tmp/gobi-reboot.log
		uci -q set luci.main.gobi_reset=0 && uci commit luci
		echo 0
		return 0
	fi
This seems to resolve my issue now that it will attempt to do the other retry / rebooting of the modem automatically.

Again, I don't know the cause of the main issue, nor do I particularly care in this moment as this "works enough" for me right now. Though if I get dropped from more meetings I'll probably dig further. Hopefully this helps you all if you're running into the same issue I am.

undertowzen
Posts: 11
Joined: Thu Oct 15, 2020 11:46 pm
Has thanked: 0
Been thanked: 2 times

Re: [SOLVED!] Losing constant Internet connection on Mofi 4500 (and my mind)

Post by undertowzen » Fri Oct 16, 2020 12:11 am

Hey all - I just came across this message board and this post today researching something and figured I'd register and reply.

I solved this issue on my router finally a few month ago and it was an issue of buffer bloat and overload due to MTU settings. By default the MTU setting on the router is set to 1500 and this is incorrect for the router and modem. I also set enable SQM with no speed Up/Down link shaping and this helps to increase my upload and download speed.

To enable SQM

Visit Network -> SQM QOS

Check Enable, set Interface name to eth0, set down and upload speed to 0, set log to silent

1.PNG

Click Queue Discipline tab

If available (must be on newer firmware) select Cake and then Piece of Cake, if on Older firmware select fq_codel and piece of cake

2.PNG

Click on Link Layer, now here you can leave this at none however if your router behaves extremely bad while downloading files then you can set this to ethernet with overhead and set the value to around 150. I would first however leave the dropdown set to none and test out first, once satisficed with setting click save and done.

3.PNG

Setting MTU

First follow this guide - https://hide.me/en/knowledgebase/how-to ... tu-values/ - to find your max MTU, in my case mine is 1430 and likely yours will be too. Make note of your results and substitute your result anywhere I list 1430 below.

Click Network -> General

Under Internet Connection in the MTU dropdown select custom and enter the value 1430 (you can only do this from a desktop browser a mobile browser will not work) - click save

4.PNG

Click on Network -> Mofi Internal Modem

Find the maximum transmission unit near the bottom and select custom and set the value to 1430 (you can only do this from a desktop browser a mobile browser will not work) - click save

5.PNG

Reboot router, hopefully afterward you will no longer see connection drop outs.

I would advise to still reboot the router once a day, I purchased this and scheduled it to power off the router and back on once a daily - https://www.amazon.com/gp/product/B07VK ... UTF8&psc=1

For best results you should set MTU to 1430 on your entire network (routers, PC, etc) but you may get by without it.

Thanks and hope this helps.

User avatar
terryjett
Posts: 395
Joined: Tue Sep 24, 2019 10:42 pm
Location: Far Side
Has thanked: 98 times
Been thanked: 85 times
Contact:

Re: [SOLVED!] Losing constant Internet connection on Mofi 4500 (and my mind)

Post by terryjett » Fri Oct 16, 2020 10:49 am

undertowzen wrote:
Fri Oct 16, 2020 12:11 am
Hey all - I just came across this message board and this post today researching something and figured I'd register and reply.

I solved this issue on my router finally a few month ago and it was an issue of buffer bloat and overload due to MTU settings. By default the MTU setting on the router is set to 1500 and this is incorrect for the router and modem. I also set enable SQM with no speed Up/Down link shaping and this helps to increase my upload and download speed.
Excellent share, thank you!

I have got to figure this out for WE826. Not sure where the MTU settings are for the WE826 running Golden Orb, but gonna search around.

Thanks again for sharing this.

patchesj
Posts: 6
Joined: Thu Oct 01, 2020 9:36 am
Has thanked: 0
Been thanked: 0

Re: [SOLVED!] Losing constant Internet connection on Mofi 4500 (and my mind)

Post by patchesj » Fri Oct 16, 2020 12:16 pm

undertowzen wrote:
Fri Oct 16, 2020 12:11 am

I solved this issue on my router finally a few month ago and it was an issue of buffer bloat and overload due to MTU settings. By default the MTU setting on the router is set to 1500 and this is incorrect for the router and modem. I also set enable SQM with no speed Up/Down link shaping and this helps to increase my upload and download speed.

To enable SQM
Thanks for the info.. I'm not exceptionally familiar with cake. Does it take into account clients on the LAN side behind NAT? In my case I have pfsense running between my mofi and my clients, so typical L3 based qos mechanisms assume everything is coming from one client. There are options for next hop, etc. but I really haven't found a good qos plan for implementing at the mofi level in this design. I just stick with what I have available on pfsense (wish it actually did cake vs codel..)

chuckkemp
Posts: 14
Joined: Fri Sep 11, 2020 9:16 pm
Has thanked: 0
Been thanked: 1 time

Re: [SOLVED!] Losing constant Internet connection on Mofi 4500 (and my mind)

Post by chuckkemp » Fri Oct 16, 2020 4:02 pm

DWRIGHTKM wrote:
Thu Oct 15, 2020 9:15 am
The disconnect/reconnect deal seams to have gone away for me. Its been a few days now and I have not noticed a disconnect.

A few days ago I switched my band 12 to band 2. Leaves are falling and I can now get a reliable connection to B2. After I did that, I have yet to notice a disconnect.

Is there a place on my Mofi4500 I can see how long my modem has been connected to the internet for?
Click on "Status" under the General Tab. You'll then get a report and under IPV4, will tell you how long you've been receiving internet and if you look above under "System" you can find out how long since your router restarted. From what I've seen the last two firmware updates just stopped the router from letting the internet freeze and once it detects that it restarts the IPV4 service precluding the need to either log in and perform a reboot or just powering down/up to restart the router. Their new method is faster than a reboot and will suffice for me until they can get a real fix, but from what I'm reading this issue isn't jut with MoFi and seems to be ATT centered.
Attachments
status2.PNG

afroken3130
Posts: 6
Joined: Wed Oct 14, 2020 10:08 am
Has thanked: 0
Been thanked: 0

Re: [SOLVED!] Losing constant Internet connection on Mofi 4500 (and my mind)

Post by afroken3130 » Fri Oct 16, 2020 6:07 pm

chuckkemp wrote:
Fri Oct 16, 2020 4:02 pm
Click on "Status" under the General Tab. You'll then get a report and under IPV4, will tell you how long you've been receiving internet and if you look above under "System" you can find out how long since your router restarted. From what I've seen the last two firmware updates just stopped the router from letting the internet freeze and once it detects that it restarts the IPV4 service precluding the need to either log in and perform a reboot or just powering down/up to restart the router. Their new method is faster than a reboot and will suffice for me until they can get a real fix, but from what I'm reading this issue isn't jut with MoFi and seems to be ATT centered.
Definitely not MOFI centered. I bought a Netgear L1120 to verify and the issue persisted. I just tried the MTU settings from above and will post back results.

afroken3130
Posts: 6
Joined: Wed Oct 14, 2020 10:08 am
Has thanked: 0
Been thanked: 0

Re: [SOLVED!] Losing constant Internet connection on Mofi 4500 (and my mind)

Post by afroken3130 » Sat Oct 17, 2020 12:12 am

afroken3130 wrote:
Fri Oct 16, 2020 6:07 pm
Definitely not MOFI centered. I bought a Netgear L1120 to verify and the issue persisted. I just tried the MTU settings from above and will post back results.
Unfortunately, the MTU settings did not resolve the issue. MOFI still shows the connection as good (and it is), but I still have to reboot my router (not the MOFI) when whatever hiccup this is happens. Verified on both my ASUS router and a brand new Synology router.

The only thing I haven't tried is using the mofi as a router as well. I've been hesitant to do this since I have a bunch of rules already setup and I hate the MOFI interface, but I don't think I have much choice now.

undertowzen
Posts: 11
Joined: Thu Oct 15, 2020 11:46 pm
Has thanked: 0
Been thanked: 2 times

Re: [SOLVED!] Losing constant Internet connection on Mofi 4500 (and my mind)

Post by undertowzen » Sat Oct 17, 2020 1:28 am

Sorry since I was new I had to wait for my post to be approved and then after that I was never notified it was posted.

I will say if anyone is using the mofi in bridge mode you need to disable it and use it in router mode with the MTU and SQM settings I mentioned. I just disabled the firewall in mine and connected my actual router to port 1 with a static ip associated with the mofi router network.

Bridge mode locks up constantly for no explainable reason and even when out of bridge mode I was only able to achieve stable connections after setting the mtu. The SQM is not 100% necessary but you will not receive full speed out of the mofi without this enabled.

undertowzen
Posts: 11
Joined: Thu Oct 15, 2020 11:46 pm
Has thanked: 0
Been thanked: 2 times

Re: [SOLVED!] Losing constant Internet connection on Mofi 4500 (and my mind)

Post by undertowzen » Sat Oct 17, 2020 1:31 am

Oh and if your main router contains a shortcut engine setting you may want to disable that. With that setting enabled on many routers I have noticed that the router will not renegotiate with the modem or gateway it’s connected to when needed, like during a reboot or after an outage.

Post Reply