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

[j2227]

Well, I thought I'd just post an update. The modem arrived and my setup was so straightforward, its clear it really doesn't need a tutorial. I just followed @undertowzen and the post mentioned earlier in this thread. After setting QoS to cake and turning off IPv6 (I don't know if that's necessary), I am up to 35Mbps down using just the MOFI antennas! I had a couple calls so far and I haven't had any dropped connections!

I still want to get a better antenna though. I haven't decided which directional one to get (yagi or log periodic) as I have no experience with antennas. I will keep track of my connection, but it's been a few days and I haven't been thrown off the network or router yet.

[chuckkemp]

Well mine has been up for 2 days 15hrs with no changes on my part. I got a text by At&t today that said "We've been enhancing our network near you! This should help you stay connected and experience faster speeds. Learn more at att.com/mynetwork " So idk if that had anything to do with the issues or the possible resolution but for now im happy I havent had to do any resets. Still middle of my billing cycle also.

I've noticed longer periods on mine too the last few days. Not sure what has happened, though I may have slacked off my demand though the wife has kept hers going at normal activity. As I write this my IPv4 connection has run almost 21 hours without a reset, nearly the same timeframe yesterday before it performed an auto reset. Perhaps ATT has made a change for the better. Running 4.3.2-std firmware.

BTW, I was running near 50 Mbs about a year ago, then a few months ago it dropped to around 25, Mbs when I noticed this drop issue. Recently I noticed I'm down to about 5 Mbs down and 17 up. Anyone else notice a drop in speed? Perhaps due to increased demand we're getting throttled?

Update 11/29/20
The MoFi modem has been up for almost 10 days and the IPV4 connection nearly 4 days, speeds are nearly the same.

[BrentV]

Mine has still been up, Going on over 4 days now. Maybe they were doing repairs or adding 5g to my area. Not sure, but this is a lot better. My speeds over the last 4 years have been steady dropping from a peak around 80 down to a low of maybe 5 down, before again coming back up to around 20-30 this year. And actually this week I saw 90 on my phone and 40 on the mofi band locked. I suspect I would get even higher speeds on mofi if I turn band lock off and let the mofi carrier aggregate, but I'm concerned if I disrupt it the disconnects will return so I'm just leaving it for now. Later when I'm forced to reset I'll play with it again lol

[farberm]

Hey so just reporting back.

First off found out a few things regarding the MTU I reported on earlier, the Sierra modems lock down the MTU of the hardware to 1430 so you will in fact have issues if you specify an MTU over 1430 - meaning you should populate 1430 all the way down the line from your modem to you client devices where you have the ability to change it manually. The MTU should get reported and hopefully automatically adopted by many devices once its set at the router but this doesn't always happen.

Secondly - continuing with the MTU - MSS clamping is required to really make sure things are sync'd together end to end, in the MOFI interface you'll find the option to enable this on the network screens on other routers you'll find it in either firewall settings or you may have to enable it via a script. On devices where you can modify the IPTables directly you can set the below config against your wan and lan interfaces, just copy paste and replace the section <wwan0> with whatever your interface name is without the < >. You'll have three entries minimum here one for lan and one for wan and the generic blanket rule - but experiment if you have additional configurations.

iptables -t mangle -A POSTROUTING -p tcp --tcp-flags SYN,RST SYN -o <wwan0> -j TCPMSS --clamp-mss-to-pmtu

I've also applied this blanket clamp rule which applies as a whole

iptables -I FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu

Thirdly, I got away from the Mofi and onto a USB enclosure connected to a router running Golden Orb Rooter firmware. My settings here are as above when it comes to MTU and as well I've always forced DNS of 1.1.1.1/1.0.0.1 or 8.8.8.8/8.8.4.4 on my interfaces, I've also enabled QOS on Golden Orb against the wwan interface using the 0 up 0 down Cake SQM I specified in a previous post. I have TTL set to 64 instead of 65 however you may have better experience on one or the other. I'm happy to report that not only do I still have no disconnects, my once a day slow downs are gone and I have 10ms lower pings AND my download speed increased from 65Mbits to 100Mbits down - my Upload however remained the same at 17Mbits.

If anyone is curious I am on AT&T Sim through UBIFI I've had the service with them since December 2019. I am band locked to band 2 and 12 for aggregation.

I am still rebooting all my routers and the modem once a day as standard practice.

Lastly, I'm sure many of you may know but the reason why the VPN is fixing a lot of problems is because it sets itself up behind its own network with its own settings which don't necessarily interact directly with your hardware in the same way a standard network would hence why it isn't having the same problems as running without it. However I do run a VPN on one of my Merlin WRT routers for online gaming and below is my additional / custom config I've found that works best for binding the VPN to the routers/modem MTU and speeds. This gives me the highest throughput and the lowest latency for my games and downloads through my VPN client. You may want to play around with the settings.


remote-cert-tls server
resolv-retry infinite
remote-random
nobind
tun-mtu-extra 0
mssfix 1303
tun-mtu 1428
persist-key
persist-tun
ping 15
ping-restart 0
ping-timer-rem
reneg-sec 0
remote-cert-tls server
nice -30


Anyways just thought I'd pass this all along in case it helps anyone out. Good luck to everyone.

Undertowzen:
Thanks for all this great work. I have a few question to complete the setup. I am using a WG1608 router with a EM20 modem and GoldenOrb. This connects directly to my Unifi USG and my home network including Unifi access points I do not use the wifi on the wg1608.

1. Set TTL to 65 - under Network-Firewall-Custom TTL settings
2. I have set the SQM QOS on wwan0 (wan1) to cake and piece of cake.
3. I tested my MTU and its 1402 which means I set it to 1430 as in your case.
4. Under Interfaces I set the following two interface MTU under Interface-(Select Interface)-Advanced Settings

• LAN (br-lan) -set override to 1430

• WAN1 (wwan0) - set override to 1430

Three additional question:

1. Do I need to change the MTU to 1430 on my Unifi USG
2. For MSS clamping I need to add the following 3 rules. Do I add these under Network-Firewall-custom Rules and are they correct?

• iptables -t mangle -A POSTROUTING -p tcp --tcp-flags SYN,RST SYN -o <wwan0> -j TCPMSS --clamp-mss-to-pmtu

• iptables -t mangle -A POSTROUTING -p tcp --tcp-flags SYN,RST SYN -o <br-lan> -j TCPMSS --clamp-mss-to-pmtu

• iptables -I FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu

3. Do I need to add any rules to the Unifi USG?

Thanks again for all your help. I will get back to you after I test it out and see it all works.

[JTontheFly]

Maybe they were doing repairs or adding 5g to my area. Not sure, but this is a lot better.

I think that is what has happened in my area. I checked the ATT coverage map a month ago and at that time I was in a dark blue 4G LTE area. Today I checked and the ATT coverage map has me solidly in aqua colored 5G area. Additionally, my router uptime without a disconnect is 13+ days. This begs the question, can I now upgrade my router and sim card to take advantage of 5G speeds? I'm going to give Ubifi a shout to see what they say. If anyone has done this please post your findings. Thanks.

[BDGLTE]

I thought I would just post my experience here as I've been working on my setup for about 9 months now and have a stable connection.
I'm using a MediaTek MT7620A with GoldenOrb_2020-05-16 firmware on ATT. My plan is AT&T unlimited.
I ordered the enclosure from amazon that included the Quectel EM-12 modem.
Once I set it all up I was receiving about 80-100MB down and about 30-80 up.
Started to experience the same issue described here where all browsing ability would stop once a day and would not come back without bouncing the router.
I loaded the ExpressVPN on to the router and that resolved browsing although slowed things down a bit.
It also would allow netflix most of the time where IPVANISH would not. Still could not get to some other services like ATT TV. I finally removed the VPN as I wanted the bandwidth back.
I finally found that there is a transparent proxy on the ATT side that is blocking port 80 and 443 after about 24 hours. This explains why I could sometimes continue a ZOOM call but loose browsing and netflix.
So if you are using OpenWRT and use the connection monitor to toggle the connection, it's not going to catch the drop because it's still connected. The issue is the proxy blocks the ports.
So, I finally scheduled a script via cron on the router using WGET to Cloudflare DNS on port 80 every minute and if it failed just power toggle the modem and not bounce the box. The end result has been that the connection drops for about 30 seconds but it's not even noticeable on netflix due to their buffering. After implementing the script, the time between drops widened to 2-3 days and not sure if it's the constant attempt to hit 1.1.1.1 every 60 seconds like a keepalive script.
But the odd thing has been that the connection normally drops between 9:31 and 11:44 in the evening.

But recently I've been up for 10 days now. I'm suspecting the same as many here that they've been upgrading the infrastructure for 5G and hopefully it's done now. I hope this helps someone

[56387f]

So, I finally scheduled a script via cron on the router using WGET to Cloudflare DNS on port 80 every minute and if it failed just power toggle the modem and not bounce the box.

This is very clever idea, this is how the connection monitor is implemented in MOFI, you have a choice of pinging or sending DNS requests to detect if the connection is alive. Actually both scenarios make sense:

a) I have been in a situation when the ISP was globally blocking all DNS requests. I was using a VPN and I could access the remote end point by its IP address (which was "almost static" i.e. normally this dynamically allocated IP could change one/two times per year), so did not care about DNS resolution at all. In this case I monitored the connection status by pinging the remote IP;

b) but when there is no VPN then DNS is vital and if the modem can ping remote site but cannot access it by its name then this is not good - in this case I would rather monitor the connection by checking for DNS resolution but unfortunately GoldenOrb does not provide such an option.

BDGLTE, would you mind sharing your script here since I think this is the great idea and very useful addition to current GoldenOrb functionality?

Thanks in advance!

[BDGLTE]

Sure no problem at all...

I have it cron'd to run every minute and I usually just ssh to router and tail the log.out to see how long it's been between disconnects. As I mentioned, I rarely even notice if it's triggered.

This my cron entry.
*/1 * * * * /bin/ash /root/test.sh >> /root/log.out 2>&1


------ test.sh below

#!/bin/bash

wget -t3 -T5 --spider --no-check-certificate -o test.out "http://1.1.1.1:80"

if [ $? -eq 0 ]; then
echo "Online" "$(date)"
if [ -f server_problem_first_time_dns.txt ]; then #removes file if second test is succesful
rm -rf server_problem_first_time_dns.txt
fi
else
echo "Offline"
if [ -f server_problem_first_time_dns.txt ]; then # —— Second time, send notification and powertoggle modem
echo "DNS PORT NOT CONNECTING" >> server_problem.txt
rm -rf server_problem_first_time_dns.txt
sendmail your_phone_number_here@mms.att.net < test.out # —— if you have att cell, would be difference for other service
/usr/lib/rooter/pwrtoggle.sh 1
rm -rf server_problem.txt
else #First notification
> server_problem_first_time_dns.txt
fi
fi

[56387f]

Sure no problem at all...

Thanks! The script is great but I am not sure about DNS check though.
The following post can be of interest to someone curious about the difference between ping vs DNS check.

https://wirelessjoint.com/viewtopic.php?f=8& ... eck#p13297

The key word there is "DNS lookup" because this is what DNS is about

Another interesting idea is:

https://wirelessjoint.com/viewtopic.php?f=10 ... it=AT+WDSC

I am not sure if it uses a DNS lookup under the hood to resolve the name of SW server otherwise it would be a very cheap and reliable way to achieve the desired result since all job is done by the modem itself.

[BillA]

According to reports, recently ATT has fixed the connection drop/transparent proxy issue (no more VPN required), where the router would stay connected but there's no traffic through the main http/https ports 80/443 (aka DNS lookup issue).
https://forums.att.com/conversations/ot ... 41?page=14

However, if you're still getting disconnected, you could try ECM mode which provides auto-reconnect when the link goes down (in case you lose the connection with the modem due to these commands, you will need to reflash it).

Quectel AT-command:

Code: Select all

AT+QCFG="usbnet"  < Status
AT+QCFG="usbnet",0  < QMI/PPP/Default
AT+QCFG="usbnet",1  < ECM
AT+QCFG="usbnet",2  < MBIM

Sierra AT-command:

Code: Select all

AT!UDUSBCOMP?  < Status
AT!UDUSBCOMP=?  < Usage Format
AT!UDUSBCOMP=<x>  < Usage

[justthompson]

Hello,

Apologies for resurrecting a thread from 2020, but The past few weeks i have begun to experience a similar issue to the OP.
I have a MOFI4500-4GXeLTE-SIM7, and use a T-mobile SIM on my phone plan in the Router.
Lately, over the past few weeks, My internet connection keeps dropping. Requiring me to go upstairs and unplug the Device, and plug it back in.
When the Connection is lost, i cannot even access the web interface at 192.168.10.1 like i usually do, therefore requiring the unplug/replug.

I searched for similar issues which lead me to this thread, so tried some things mentioned here.
I do have a VPN service, and even when i have multiple devices connected to Nord VPS, the random drops keep happening.

I am beginning to wonder if my Device is just going bad, and i need to replace it with something better.

[BillA]

Hello,

Apologies for resurrecting a thread from 2020, but The past few weeks i have begun to experience a similar issue to the OP.
I have a MOFI4500-4GXeLTE-SIM7, and use a T-mobile SIM on my phone plan in the Router.
Lately, over the past few weeks, My internet connection keeps dropping. Requiring me to go upstairs and unplug the Device, and plug it back in.
When the Connection is lost, i cannot even access the web interface at 192.168.10.1 like i usually do, therefore requiring the unplug/replug.

I searched for similar issues which lead me to this thread, so tried some things mentioned here.
I do have a VPN service, and even when i have multiple devices connected to Nord VPS, the random drops keep happening.

I am beginning to wonder if my Device is just going bad, and i need to replace it with something better.

Sorry for the late reply, but if you can't even access your router's web interface at 192.168.10.1, that's a local issue with your router, not the carrier.