Wireless Joint

Hoping to get some kind input regarding my maddening situation. I am currently on the Tmobile magenta max phone plan and am being throttled to 5bps. Each night I'll tweak TTL and VPN settings and restart my modem and will see 20-30mbps download speeds . Then I'll go to sleep satisfied with my accomplishment, only to run a speedtest in the morning and see speeds of 5mbps . Here's my setup:

Netgear M1 (with Tmobile sim and repaired IMEI) connected via ethernet to --> OpenWrt router (with iptables-mod-ipopt installed) connected via ethernet to --> Home Wifi router

I have the OpenWrt router in the mix to alter TTL and provide the VPN layer. My router has the following interfaces, which I have tested with IPV6 both enabled and disabled:

br-lan - bridge
eth0 - WAN
eth1 - LAN
wg0 - VPN

As far as VPN goes, I have utilized both wireguard and openvpn without any luck. For TTL I have tried the following:

#config 1
ip6tables -t mangle -A POSTROUTING -o eth0 -j HL --hl-set 66
iptables -t mangle -I PREROUTING -i eth0 -j TTL --ttl-set 66

#config 2
iptables -t mangle -I POSTROUTING -o eth0 -j TTL --ttl-set 66

#config 3
ip6tables -t mangle -I POSTROUTING -o eth0 -j HL --hl-set 67
iptables -t mangle -I POSTROUTING -o eth0 -j TTL --ttl-set 66

I am at a loss as to what identifies me as using a hotspot! Any ideas? Thanks ahead of time for any input anyone may have.

Here is what I use for Verizon--make sure your (APN) is correct for your carrier.

#startTTL
iptables -t mangle -I POSTROUTING -j TTL --ttl-set 64
iptables -t mangle -I PREROUTING -j TTL --ttl-set 64
ip6tables -t mangle -I POSTROUTING -j HL --hl-set 64
ip6tables -t mangle -I PREROUTING -j HL --hl-set 64
#endTTL

TTL is used to mask hotspot use. If for some reason they are seeing hotspot data and you have used your limit of hotspot data, your done for that billing cycle and there is no resetting to get speeds back. The fact that you can reset the modem and get speeds back makes me think it is something other than hotspot related. Does it seem to be a hard limit exactly at 5mbps? Maybe its jumping bands on you after being connected for awhile? Do you have access to telnet port on your MR1100? You can telnet in and run AT!GSTATUS? and see which primary and secondary bands are in use and then run it again when it slows down and see if they have changed.

Also, your TTL settings may be incorrect? Assuming you have the ethernet cable from the M1 to the "WAN" port of the Openwrt router? Check your Openwrt router and see which interface is your WAN interface. Typically LAN=eth0 and WAN=eth1 but could be different in your scenario. If WAN=eth1 then your TTL mangle settings need to be revised so the that TTL will be modified on the outgoing packets on WAN/eth1 rather than eth0.

Also just as fyi, I believe Tmo TTL is typically 65 but since your TTL modifications set 1 device further behind the actual 'provider connection' then a TTL setting of 66 would be correct from my understanding.

I don't know of any reasons to 'need' to use VPN with Tmo..

Used to T-Mobile phone card sim in a WE826 with MC7455 or a EP06 or EM12.
Always had the TTL set to 64. Worked great no issues.
Maybe would do better with a cleaner set up like that instead of this Dixie chain of routers.
Just a thought.

mtl26637 wrote: ↑Sun Dec 12, 2021 10:16 am TTL is used to mask hotspot use. If for some reason they are seeing hotspot data and you have used your limit of hotspot data, your done for that billing cycle and there is no resetting to get speeds back. The fact that you can reset the modem and get speeds back makes me think it is something other than hotspot related. Does it seem to be a hard limit exactly at 5mbps? Maybe its jumping bands on you after being connected for awhile? Do you have access to telnet port on your MR1100? You can telnet in and run AT!GSTATUS? and see which primary and secondary bands are in use and then run it again when it slows down and see if they have changed.

@mtl26637 - You nailed it! Telnetted in to the modem, ran AT!GSTATUS?. and found that when on Band 12 I was being limited to 5mbps down. When on B2 +B12 CA, or even only on B2, I started getting 20mbps again. Thank you very much for the suggestion! Any idea why that particular band would throttle?

Awesome job @mtl26637.

Little Nuggets of gold like this make reading all the post worthwhile

luke37 wrote: ↑Thu Dec 16, 2021 7:05 pm
@mtl26637 - You nailed it! Telnetted in to the modem, ran AT!GSTATUS?. and found that when on Band 12 I was being limited to 5mbps down. When on B2 +B12 CA, or even only on B2, I started getting 20mbps again. Thank you very much for the suggestion! Any idea why that particular band would throttle?

Band 12 has very little bandwith, usually at 5mhz where they own it. The whole band maxes out at around 38mbps in perfect conditions, so if you don't have perfect band 12 signal and no other users on that tower, a few mbps is the most you can push out of it.

This is exactly the setup that I'm going to eventually have. Still working on setting it all up. Since you determined that it wasn't hotspot detection as the reason you were being throttled, how can you tell whether or not your setup is successfully circumventing hotspot detection?