Reg: IPv6 on MC7354

Tue Feb 7 22:06:09 UTC 2017

Balaji Sivakumar <shivbalaji1985 at gmail.com> writes:

> Hi,
>
> I am able to start the network using ip-type for ipv6 and it is getting
> connected. Also able to get the current settings using
> "--wds-get-current-settings". But the thing am not getting the expected the
> Ipv6 address , it is getting generated on the fly whenever we read current
> settings. Am always getting expected dns ip address "IPv6 primary DNS".
>
> did anyone face this  issue? any suggestions.

This is normal.  The modem is assigned a /64 prefix, which is what it
will announce in the RAs.  You can use whatever address you want within
this prefix.  They will all work.

The modem generates what seems to be pseudo random interface ids, and a
new one for every request like you have noticed. I recommend using one
of the standard addrgenmodes instead.

The exact same behaviour can be observed with an EM7455 in MBIM mode.
Getting a new address for every IP config request, but notice that the
prefix stays the same:

root at miraculix:/tmp#  mbimcli -p -d /dev/cdc-wdm0 --query-ip-configuration=0

[/dev/cdc-wdm0] IPv4 configuration available: 'address, gateway, dns, mtu'
     IP [0]: '10.169.23.118/30'
    Gateway: '10.169.23.117'
    DNS [0]: '193.213.112.4'
    DNS [1]: '130.67.15.198'
        MTU: '1500'

[/dev/cdc-wdm0] IPv6 configuration available: 'address, gateway, dns, mtu'
     IP [0]: '2a02:2121:2c3:d006:8dc7:5dd9:4c49:58fd/64'
    Gateway: '2a02:2121:2c3:d006:b0c3:7e25:7b93:fcbc'
    DNS [0]: '2001:4600:4:fff::52'
    DNS [1]: '2001:4600:4:1fff::52'
        MTU: '1500'
root at miraculix:/tmp#  mbimcli -p -d /dev/cdc-wdm0 --query-ip-configuration=0

[/dev/cdc-wdm0] IPv4 configuration available: 'address, gateway, dns, mtu'
     IP [0]: '10.169.23.118/30'
    Gateway: '10.169.23.117'
    DNS [0]: '193.213.112.4'
    DNS [1]: '130.67.15.198'
        MTU: '1500'

[/dev/cdc-wdm0] IPv6 configuration available: 'address, gateway, dns, mtu'
     IP [0]: '2a02:2121:2c3:d006:3864:624d:ba7f:9cc3/64'
    Gateway: '2a02:2121:2c3:d006:b0c3:7e25:7b93:fcbc'
    DNS [0]: '2001:4600:4:fff::52'
    DNS [1]: '2001:4600:4:1fff::52'
        MTU: '1500'
root at miraculix:/tmp#  mbimcli -p -d /dev/cdc-wdm0 --query-ip-configuration=0

[/dev/cdc-wdm0] IPv4 configuration available: 'address, gateway, dns, mtu'
     IP [0]: '10.169.23.118/30'
    Gateway: '10.169.23.117'
    DNS [0]: '193.213.112.4'
    DNS [1]: '130.67.15.198'
        MTU: '1500'

[/dev/cdc-wdm0] IPv6 configuration available: 'address, gateway, dns, mtu'
     IP [0]: '2a02:2121:2c3:d006:794a:cd8a:6b42:5952/64'
    Gateway: '2a02:2121:2c3:d006:b0c3:7e25:7b93:fcbc'
    DNS [0]: '2001:4600:4:fff::52'
    DNS [1]: '2001:4600:4:1fff::52'
        MTU: '1500'

The address actually assigned by NM is none of the above:

root at miraculix:/tmp# ip addr show dev wwan0
11: wwan0: <BROADCAST,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN group default qlen 1000
    link/ether 52:55:d2:c6:23:af brd ff:ff:ff:ff:ff:ff
    inet 10.169.23.118/30 brd 10.169.23.119 scope global wwan0
       valid_lft forever preferred_lft forever
    inet6 2a02:2121:2c3:d006:f80d:e8fa:714a:a351/64 scope global 
       valid_lft forever preferred_lft forever

You can also use nice "short" addresses if you like. This works, for example:

root at miraculix:/tmp# ip addr add 2a02:2121:2c3:d006:: dev wwan0
root at miraculix:/tmp# traceroute6 -s 2a02:2121:2c3:d006:: google.com 
traceroute to google.com (2a00:1450:400f:807::200e) from 2a02:2121:2c3:d006::, port 33434, from port 49907, 30 hops max, 60 bytes packets
 1  2a02:2121:2c3:d006:0:9:8dcc:b040 (2a02:2121:2c3:d006:0:9:8dcc:b040)  262.977 ms  45.760 ms  169.485 ms 
 2  * * *         
 3  2a02:2120::2000:0:0:31 (2a02:2120::2000:0:0:31)  177.944 ms  61.263 ms  177.280 ms 
 4  ti280830540j370-ae1-20.ti.telenor.net (2001:4600:a:101::5b2)  61.289 ms  177.334 ms  50.776 ms 
 5  ti0001a401-ae14-21.ti.telenor.net (2001:4600:9:500:1::55)  177.736 ms  51.664 ms  78.161 ms 
 6  ti0300c360-lo0-0.ti.telenor.net (2001:4600:0:100::2a)  60.457 ms  88.834 ms  55.538 ms 
 7  ti3163c360-lo0-0.ti.telenor.net (2001:4600:0:100::10)  87.000 ms  55.456 ms  27.921 ms 
 8  ti3001b400-lo0-0.ti.telenor.net (2001:4600::11)  55.952 ms  29.897 ms  66.357 ms 
 9  2001:4860:1:1:0:847:: (2001:4860:1:1:0:847::)  29.933 ms  66.192 ms  70.005 ms 
10  2001:4860::1:0:26eb (2001:4860::1:0:26eb)  66.107 ms  69.878 ms  53.959 ms 
11  2001:4860:0:1::1013 (2001:4860:0:1::1013)  71.772 ms  54.994 ms  55.003 ms 
12  arn09s11-in-x0e.1e100.net (2a00:1450:400f:807::200e)  53.523 ms  54.239 ms  89.773 ms 

Hope you get the idea.. 

Bjørn