Strange name of interface wwan0

Hardware Librem 5
1

Why ifconfig -a shows the interface wwan0 with this name:

...
wwx06ff17846e25: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST>  mtu 1500
        inet 10.135.62.140  netmask 255.255.255.248  destination 10.135.62.140
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 1000  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 5  bytes 236 (236.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
2

That name is generated using wwan prefix “ww” and device MAC address, if I interpret this correctly.

https://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/

1 Like
3

Maybe, but normally it is just wwan0 and not such generated name.

4

Well, it says that starting with systemd v197, the naming scheme changed:

Starting with v197 systemd/udev will automatically assign predictable, stable network interface names for all local Ethernet, WLAN and WWAN interfaces. This is a departure from the traditional interface naming scheme (“eth0”, “eth1”, “wlan0”, …), but should fix real problems.

Since you didn’t state what distro are you using, and at what point the change occurred, I can’t be sure what happened. It might be that you’ve updated your system, which caused systemd v197 to be installed, and your wwan interface got renamed as per new policy.

There is an explanation on how to disable it at the end of the article.

5

I have a complete uptodate L5 and systemd is:

purism@pureos:~$ systemd --version
systemd 247 (247.3-7+deb11u1)
+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +ZSTD +SECCOMP +BLKID +ELFUTILS +KMOD +IDN2 -IDN +PCRE2 default-hierarchy=unified

I saw this interface name already in the past on my L5 and now again after a reboot. Before it was wwan0. I.e. this issue must be more complex.

6

I rebooted and now it says:

wwan0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST>  mtu 1500
        inet 10.127.171.226  netmask 255.255.255.252  destination 10.127.171.226
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 1000  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 5  bytes 236 (236.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
7

It’s peculiar indeed. Linux networking configuration is not really my forte, and I also don’t have a SIM card in my Librem 5, so I can’t investigate that for you. Maybe someone more experienced than I can jump in and explain it.