Rebooting is not the best way to fix the problem.As far as I know, some modems cannot retrieve the IP after the IP address of QMI protocol expires.
Don't edit the file directly, it will be lost on next reboot.
Instead add the nameservers under the lan or wan interface configuration.
option dns '8.8.8.8 8.8.4.4'
I edited the /etc/config/network file adding the dns option to my wan section
but I couldn't find a way to check which nameservers I am using
root@OpenWrt:~# nslookup google.com
Server: 127.0.0.1
Address: 127.0.0.1#53
You can check it at www.dnsleaktest.com
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at that link I can only see my ip
I'm behind a double nat for my MVNO provider, maybe this is the reason
same happen if I enable OpenVPN, the link shows my VPN ip
you need to click standard test button ,it will show show your ISP,if you seting DNS server is 8.8.8.8，the ISP will show GOOGLE
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You can run a tcpdump on wan/vpn interface for udp 53 and verify which upstream nameservers are you quering.
the ISP part says GOOGLE
doing tcpdump -ni wlan0 port 53 also shows 8.8.8.8 nameserver used
but in my /etc/config/network there are OpenDns ones
config interface 'wan'
option ifname 'eth0.2'
option proto 'dhcp'
option dns '208.67.222.222 208.67.220.220
Can be explained as a lot of mobile phones or tablets come with hardcoded Google nameservers. You'll need to hijack the DNS traffic in order to enforce the locally configured NS.
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cool, I'll try this too but now there is a new issue
the wwan interface does not connect anymore
these are the last line of the log when I stopped and connected again the interface
Thu Apr 4 16:50:19 2019 daemon.notice netifd: wwan (1829): Stopping network wwan
Thu Apr 4 16:50:19 2019 daemon.notice netifd: wwan (1829): Command failed: Permission denied
Thu Apr 4 16:50:19 2019 daemon.notice netifd: Interface 'wwan' is now down
Thu Apr 4 16:50:31 2019 daemon.notice netifd: Interface 'wwan' is setting up now
Thu Apr 4 16:50:31 2019 daemon.notice netifd: wwan (1885): "No effect"
Thu Apr 4 16:50:32 2019 daemon.notice netifd: wwan (1885): Waiting for network registration
PS: I restarted manually several times, disconnected the plug, checked the mobile sim card for expiration and giga availability
thanks to everybody who shared possible solutions to this issue, but before i try them i would like to contact the maintainer of the dwr-921. does anybody know who that is and how to reach him/her?
Here's a list of exactly all the configuration that was done on this device after flashing openwrt:
passwd
uci set network.wwan=interface
uci set network.wwan.proto='qmi'
uci set network.wwan.device='/dev/cdc-wdm0'
uci set network.wwan.apn='internet'
uci set network.wwan.modes='lte'
uci commit network
uci set firewall.@zone[1].network='wan wwan wan6'
uci commit firewall
ifup wwan
opkg update
opkg install luci-proto-qmi
/etc/init.d/uhttpd restart
reboot
The instructions on the wiki page for this router are different. See: https://openwrt.org/toh/d-link/d-link_dwr-921
I just flashed this modem. Which ones should I follow?
Thank you.
I used the first approach with uci set network.wwan.proto='wwan'
I also have the C3 version and the hanging problem.
Thanks to this discussion I configured the router now for a nightly reboot. Let‘s see, if this helps. However I did not get the point how dns configuration helps. Did the OpenDNS approach finally help?
If this plays any role, I use a Wireguard VPN tunnel to get a connection to the router via my dsl router.
A little update: the reboot via cronjob does not help at all in my case, because the 4g modem often still hangs after reboot.
There is one interesting thing: Using a vodafone sim, the modem seems to be stable, but with a congstar (t-mobile) sim it hangs after about 2 days. Could the modem hangs be somehow related to the 4g frequency/band? Or are there other differences between providers that might matter?
Another update: today I got the dlink back from the holiday flat where I used him for IOT purposes and lost the vpn access for a few weeks. As I assumed before, the congstar sim is defective in my case. The strange thing is, that it seemed to fail slowly and now it is not detected anymore at all. I put it into a 4g usb stick and smartphone telling me "no sim card found". So I ordered an exchange sim. I will report if the hangs still continue with the new sim.
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I got a new sim from Congstar. Now it runs smoothly, not hanging anymore for a week now.
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