[USB 3G Modem] Very *strange* problem

grufo · 2014-08-19 12:50:14

Hi all!

Here is my strange problem. My USB 3G Modem was working well until a recent update. Then, it started to behave in the following strange way: it seems to perfectly connect, but de facto the computer cannot navigate.

Here is my ifconfig output:

$ ifconfig

eno1: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        ether a4:5d:36:78:90:1f  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

enp0s18f2u1i5: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.124.245.176  netmask 255.255.255.0  broadcast 10.124.245.255
        ether 02:6a:af:79:e4:50  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 411  bytes 17602 (17.1 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 0  (Local Loopback)
        RX packets 2043  bytes 166615 (162.7 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2043  bytes 166615 (162.7 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

wlo1: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        ether bc:85:56:15:e1:b5  txqueuelen 1000  (Ethernet)
        RX packets 7455  bytes 8982959 (8.5 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 5712  bytes 665141 (649.5 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

After spending some time, I discovered that the only way to use internet is to launch:

$ sudo systemctl start dhcpcd@enp0s18f2u1i5

…and, by doing so, internet works. But, NetworkManager must be active, otherwise it doesn't!

How is it possible that now I need to activate dhcpcd together with NetworkManager to navigate, while until some days ago dhcpcd was always off and everything worked fine?

Here is my USB modem:

$ lsusb
Bus 004 Device 002: ID 04f2:b3a6 Chicony Electronics Co., Ltd 
Bus 004 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 003: ID 19d2:1522 ZTE WCDMA Technologies MSM 
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Thank you very much for any kind of help!

*grufo*

lahwaacz · 2014-08-19 13:10:34

The wiki says that NetworkManager uses dhclient by default and falls back to dhcpcd in case dhclient is not installed.

grufo · 2014-08-20 09:42:04

@lahwaacz

lahwaacz wrote:

The wiki says that NetworkManager uses dhclient by default and falls back to dhcpcd in case dhclient is not installed.

Thank you for your answer!

I never had dhclient installed, but until some days ago everything has been automatic. However, now I installed dhclient. Nevertheless nothing changed: I still have to launch:

$ sudo systemctl start dhcpcd@enp0s18f2u1i5

*grufo*

EDIT: I discovered another very annoying stuff! If I don't use my computer for some minutes, when I come back I have to launch that command again

Last edited by grufo (2014-08-20 09:47:55)

lahwaacz · 2014-08-20 22:00:59

What is dumped into the journal when you run NetworkManager (alone, without manually starting dhcpcd)?

NetworkManager should launch dhcpcd by itself, so 'ps' should see it. You could also check /etc/NetworkManager/NetworkManager.conf ...

grufo · 2014-08-21 10:53:27

lahwaacz wrote:

What is dumped into the journal when you run NetworkManager (alone, without manually starting dhcpcd)?
NetworkManager should launch dhcpcd by itself, so 'ps' should see it. You could also check /etc/NetworkManager/NetworkManager.conf ...

This is the only one section of the last journal that regards the USB 3G Modem in NetworkManager…:

$ journalctl -b
-- Logs begin at ven 2014-01-10 17:20:52 CET, end at gio 2014-08-21 12:36:56 CEST. --
[…]
ago 21 12:24:14 alba NetworkManager[287]: <info> new connection /etc/NetworkManager/system-connections/drei-at_usb_internet
ago 21 12:24:14 alba NetworkManager[287]: <info> monitoring kernel firmware directory '/usr/lib/firmware'.
ago 21 12:24:14 alba NetworkManager[287]: <info> rfkill0: found WiFi radio killswitch (at /sys/devices/pci0000:00/0000:00:04.0/0000:02:00.0/ieee80211/
ago 21 12:24:14 alba NetworkManager[287]: <info> WiFi hardware radio set enabled
ago 21 12:24:14 alba NetworkManager[287]: <info> WWAN hardware radio set enabled
ago 21 12:24:14 alba NetworkManager[287]: <info> Loaded device plugin: /usr/lib/NetworkManager/libnm-device-plugin-wifi.so
ago 21 12:24:14 alba NetworkManager[287]: <info> Loaded device plugin: /usr/lib/NetworkManager/libnm-device-plugin-adsl.so
ago 21 12:24:14 alba NetworkManager[287]: <info> Loaded device plugin: /usr/lib/NetworkManager/libnm-device-plugin-wwan.so
ago 21 12:24:14 alba NetworkManager[287]: <info> Loaded device plugin: /usr/lib/NetworkManager/libnm-device-plugin-bluetooth.so
ago 21 12:24:14 alba NetworkManager[287]: <info> WiFi enabled by radio killswitch; enabled by state file
ago 21 12:24:14 alba NetworkManager[287]: <info> WWAN enabled by radio killswitch; enabled by state file
ago 21 12:24:14 alba NetworkManager[287]: <info> WiMAX enabled by radio killswitch; enabled by state file
ago 21 12:24:14 alba NetworkManager[287]: <info> Networking is enabled by state file
ago 21 12:24:14 alba NetworkManager[287]: <info> (lo): link connected
ago 21 12:24:14 alba NetworkManager[287]: <info> (lo): carrier is ON
ago 21 12:24:14 alba NetworkManager[287]: <info> (lo): new Generic device (driver: 'unknown' ifindex: 1)
ago 21 12:24:14 alba NetworkManager[287]: <info> (lo): exported as /org/freedesktop/NetworkManager/Devices/0
ago 21 12:24:14 alba NetworkManager[287]: <info> (eno1): carrier is OFF
ago 21 12:24:14 alba NetworkManager[287]: <info> (eno1): new Ethernet device (driver: 'r8169' ifindex: 2)
ago 21 12:24:14 alba NetworkManager[287]: <info> (eno1): exported as /org/freedesktop/NetworkManager/Devices/1
ago 21 12:24:14 alba NetworkManager[287]: <info> (eno1): device state change: unmanaged -> unavailable (reason 'managed') [10 20 2]
[…]

And this is the section of the last journal that regards my manual start of the dhcpcd@enp0s18f2u1i5 service:

[…]
ago 21 12:31:52 alba sudo[1041]: grufo : TTY=pts/0 ; PWD=/home/grufo ; USER=root ; COMMAND=/usr/bin/systemctl start dhcpcd@enp0s18f2u1i5
ago 21 12:31:52 alba sudo[1041]: pam_unix(sudo:session): session opened for user root by grufo(uid=0)
ago 21 12:31:53 alba dhcpcd[1044]: version 6.4.3 starting
ago 21 12:31:53 alba ModemManager[286]: <info>  Modem /org/freedesktop/ModemManager1/Modem/0: signal quality updated (80)
ago 21 12:31:53 alba dhcpcd[1044]: DUID 00:01:00:01:19:bb:e1:8e:a4:5d:36:78:90:1f
ago 21 12:31:53 alba dhcpcd[1044]: enp0s18f2u1i5: IAID af:79:e4:50
ago 21 12:31:53 alba ModemManager[286]: <info>  Modem /org/freedesktop/ModemManager1/Modem/0: signal quality updated (45)
ago 21 12:31:53 alba dhcpcd[1044]: enp0s18f2u1i5: rebinding lease of 10.137.147.199
ago 21 12:31:53 alba dhcpcd[1044]: enp0s18f2u1i5: NAK: from 10.138.210.187
ago 21 12:31:53 alba dhcpcd[1044]: enp0s18f2u1i5: soliciting a DHCP lease
ago 21 12:31:53 alba dhcpcd[1044]: enp0s18f2u1i5: offered 10.138.210.186 from 10.138.210.187
ago 21 12:31:53 alba dhcpcd[1044]: enp0s18f2u1i5: leased 10.138.210.186 for 86400 seconds
ago 21 12:31:53 alba dhcpcd[1044]: enp0s18f2u1i5: adding route to 10.138.210.0/24
ago 21 12:31:53 alba dhcpcd[1044]: enp0s18f2u1i5: adding default route via 10.138.210.187
ago 21 12:31:53 alba dhcpcd[1044]: forked to background, child pid 1095
[…]

*grufo*

grufo · 2014-09-08 11:34:38

I solved! Just following this paragraph

*grufo*

EDIT: False alarm. It still doesn't work properly

Last edited by grufo (2014-09-08 12:03:34)

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#1 2014-08-19 12:50:14