<div dir="ltr"><div>Hi Amol, > MTU from the carrier is 1360 but wwan0 MTU is set to 1500. It must be set to the MTU received from the carrier.</div> Thank you for your suggestion! I added the correct MTU value setting.<div>However, it looks like it's not the cause of this specific problem, after changing the MTU and resetting the ModemManager, or after changing MTU, resetting ModemManager and resetting the modem, the issue still persists. # ifconfig wwan0 wwan0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 inet addr:100.65.37.39 P-t-P:100.65.37.39 Mask:255.255.255.240 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1360 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:11 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:696 (696.0 B) # ping 8.8.8.8 PING 8.8.8.8 (8.8.8.8): 56 data bytes ^C --- 8.8.8.8 ping statistics --- 12 packets transmitted, 0 packets received, 100% packet loss # Do you have an idea what this issue can be caused by, or how to recover the network access on the devices? <div><div dir="ltr" data-smartmail="gmail_signature"><div dir="ltr">Kind regards, Filip</div></div></div> </div></div> <div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Jul 15, 2022 at 3:30 PM Amol Lad <<a href="mailto:Amol.Lad@4rf.com" target="_blank">Amol.Lad@4rf.com</a>> wrote: </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> <div> <div>Also, one thing I noticed in <a href="http://mmcli-all-log.info" target="_blank">mmcli-all-log.info</a>. It might not be related to your problem though. MTU from the carrier is 1360 but wwan0 MTU is set to 1500. It must be set to the MTU received from the carrier. -----Original Message----- From: Amol Lad <<a href="mailto:Amol.Lad@4rf.com" target="_blank">Amol.Lad@4rf.com</a>> Sent: Friday, 15 July 2022 6:39 PM To: Filip Kubicz <<a href="mailto:filip.kubicz@tier.app" target="_blank">filip.kubicz@tier.app</a>> Cc: <a href="mailto:modemmanager-devel@lists.freedesktop.org" target="_blank">modemmanager-devel@lists.freedesktop.org</a>; Kamil Sroka <<a href="mailto:kamil.sroka@tier.app" target="_blank">kamil.sroka@tier.app</a>> Subject: RE: Linux system cannot use the data connection Please try below (skip dns resolution) wget <a href="http://193.63.62.31/sites/default/files/publications/civic_renewal_forms.zip" target="_blank">http://193.63.62.31/sites/default/files/publications/civic_renewal_forms.zip</a> From: Filip Kubicz <<a href="mailto:filip.kubicz@tier.app" target="_blank">filip.kubicz@tier.app</a>> Sent: Friday, 15 July 2022 6:29 PM To: Amol Lad <<a href="mailto:Amol.Lad@4rf.com" target="_blank">Amol.Lad@4rf.com</a>> Cc: <a href="mailto:modemmanager-devel@lists.freedesktop.org" target="_blank">modemmanager-devel@lists.freedesktop.org</a>; Kamil Sroka <<a href="mailto:kamil.sroka@tier.app" target="_blank">kamil.sroka@tier.app</a>> Subject: Re: Linux system cannot use the data connection Hi Amol, # wget <a href="http://speedtest.ftp.otenet.gr/files/test10Mb.db" target="_blank">http://speedtest.ftp.otenet.gr/files/test10Mb.db</a> --1970-01-04 01:06:40-- <a href="http://speedtest.ftp.otenet.gr/files/test10Mb.db" target="_blank">http://speedtest.ftp.otenet.gr/files/test10Mb.db</a> Resolving speedtest.ftp.otenet.gr... failed: Temporary failure in name resolution. wget: unable to resolve host address '<a href="http://speedtest.ftp.otenet.gr" target="_blank">speedtest.ftp.otenet.gr</a><<a href="http://speedtest.ftp.otenet.gr" target="_blank">http://speedtest.ftp.otenet.gr</a>>' Filip On Fri, Jul 15, 2022 at 2:52 PM Amol Lad <<a href="mailto:Amol.Lad@4rf.com" target="_blank">Amol.Lad@4rf.com</a><mailto:<a href="mailto:Amol.Lad@4rf.com" target="_blank">Amol.Lad@4rf.com</a>>> wrote: Please also try downloading a test file as below and see the result. Does it download any file at all? wget <a href="http://speedtest.ftp.otenet.gr/files/test10Mb.db" target="_blank">http://speedtest.ftp.otenet.gr/files/test10Mb.db</a> From: Filip Kubicz <<a href="mailto:filip.kubicz@tier.app" target="_blank">filip.kubicz@tier.app</a><mailto:<a href="mailto:filip.kubicz@tier.app" target="_blank">filip.kubicz@tier.app</a>>> Sent: Friday, 15 July 2022 5:28 PM To: Amol Lad <<a href="mailto:Amol.Lad@4rf.com" target="_blank">Amol.Lad@4rf.com</a><mailto:<a href="mailto:Amol.Lad@4rf.com" target="_blank">Amol.Lad@4rf.com</a>>> Cc: <a href="mailto:modemmanager-devel@lists.freedesktop.org" target="_blank">modemmanager-devel@lists.freedesktop.org</a><mailto:<a href="mailto:modemmanager-devel@lists.freedesktop.org" target="_blank">modemmanager-devel@lists.freedesktop.org</a>>; Kamil Sroka <<a href="mailto:kamil.sroka@tier.app" target="_blank">kamil.sroka@tier.app</a><mailto:<a href="mailto:kamil.sroka@tier.app" target="_blank">kamil.sroka@tier.app</a>>> Subject: Re: Linux system cannot use the data connection Hi Amol, thanks for the answer. I checked that the devices are not hitting the SIM data limit. Moreover, as I mentioned there is some small RX/TX occurring for the device from the operator point of view, but the "ping 8.8.8.8 -I wwan0" does not work. Filip On Fri, Jul 15, 2022 at 1:28 PM Amol Lad <<a href="mailto:Amol.Lad@4rf.com" target="_blank">Amol.Lad@4rf.com</a><mailto:<a href="mailto:Amol.Lad@4rf.com" target="_blank">Amol.Lad@4rf.com</a>>> wrote: I generally run into similar situation when my SIM card runs out of money. Do you want to try topping-up SIM card and see if ping is successful? Amol From: ModemManager-devel <<a href="mailto:modemmanager-devel-bounces@lists.freedesktop.org" target="_blank">modemmanager-devel-bounces@lists.freedesktop.org</a><mailto:<a href="mailto:modemmanager-devel-bounces@lists.freedesktop.org" target="_blank">modemmanager-devel-bounces@lists.freedesktop.org</a>>> On Behalf Of Filip Kubicz Sent: Friday, 15 July 2022 4:14 PM To: <a href="mailto:modemmanager-devel@lists.freedesktop.org" target="_blank">modemmanager-devel@lists.freedesktop.org</a><mailto:<a href="mailto:modemmanager-devel@lists.freedesktop.org" target="_blank">modemmanager-devel@lists.freedesktop.org</a>> Cc: Kamil Sroka <<a href="mailto:kamil.sroka@tier.app" target="_blank">kamil.sroka@tier.app</a><mailto:<a href="mailto:kamil.sroka@tier.app" target="_blank">kamil.sroka@tier.app</a>>> Subject: Linux system cannot use the data connection Hi! I'm using ModemManager 1.18.6 with Quectel EG21-G modem and Twilio SuperSIM. This setup works ok on multiple devices. However, on a few devices, I see following situation: • Modem registered to operator network (e.g. Vodafone UK) • Modem reports connected state • wwan0 interface has IPv4 address • Network provider sees no issues • in Network provider console you can see the device exchanges a few hundred kB of data every hour • but ping doesn’t work • sending data fails This looks strange, as if ModemManager was not aware of the data session that is setup, or Linux system not being able to use it. The simplified flow of using the modem: - enable modem - wait until it auto-registers - create a bearer and connect - when bearer obtains IP address, configure the network interface I attached relevant mmcli information from the device (modem, bearer) and debug level logs from 2 situations: - device stable in connected state (but ping fails) - modem reset - sequence of enable, register, connect -> goes into the same state where ping does not work. I also attached the commands that are used for setting up the network interface when a new IP address is obtained. What should I check, or do you know how to avoid this situation? Kind regards, Filip ________________________________ The information in this email communication (inclusive of attachments) is confidential to 4RF Limited and the intended recipient(s). If you are not the intended recipient(s), please note that any use, disclosure, distribution or copying of this information or any part thereof is strictly prohibited and that the author accepts no liability for the consequences of any action taken on the basis of the information provided. 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