On Tue, Apr 18, 2023 at 11:26 AM Carlos E. R. <robin.listas@telefonica.net> wrote:
Why two, what's the difference?
Telcontar:~ # ip addr
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 00:d8:... altname enp34s0 inet 192.168.1.14/16 brd 192.168.255.255 scope global eth0 valid_lft forever preferred_lft forever inet6 2a02:9140:1180:0:634a:...:...:.../64 scope global temporary dynamic valid_lft 86397sec preferred_lft 80397sec inet6 2a02:9140:1180:0:2d8:..:...:.../64 scope global dynamic mngtmpaddr valid_lft 86397sec preferred_lft 86397sec inet6 fe80::2d8:...:...:.../64 scope link valid_lft forever preferred_lft forever Telcontar:~ #
One address is permanent, another one is temporary which is changed by kernel periodically. Kernel will prefer temporary address for outgoing connection.
Ah. I see.
But both change, the ISP changes it. It is a promise they did :-/
"permanent" vs "temporary" has nothing to do with ISP. It refers to a 64 bit interface identifier which is used to form a full IPv6 address and is managed by your system (user space, kernel or both). What happens to the prefix which is managed by the router (and finally by your ISP in this case) is out of scope here.