Adding link local address

Question

If the IPv6 link-local address is manually deleted on an interface, is there a way to obtain the link-local address back without bringing the interface down? The requirement stems from the need to hold onto (IPv4) existing connections on the interface, but also obtain the link-local address on it.

What operating system? I tested on Linux, and deleting the link-local address and readding it "just works". — Celada, Feb 29 '12 at 15:48
On Linux. I couldn't quite understand you, could you elaborate on the steps? — Maddy, Mar 01 '12 at 04:29
Steps are already elaborated by [sleinen](http://stackoverflow.com/users/1187852/sleinen). Note that it's nothing more than the same command you would use normally to add an address to the interface! — Celada, Mar 01 '12 at 14:55

score 19 · Accepted Answer · edited Mar 01 '12 at 14:13

19

GNU/Linux systems typically use "ip" (from the "iproute" package) to configure addresses. A link-local address would be added using something like

ip address add dev eth4 scope link fe80::21b:21ff:febb:5db0/64

Did you try that?

If your problem is that you don't know what exact address you should use as the link-local address: These addresses are typically derived from the hardware (MAC) address of the interface.

Take the MAC address of the interface (the "link/ether" field in the result of "ip link show dev ..."), and convert it to Modified EUI-64 according to this procedure.

Then add "fe80::" (standard link-local prefix) to the left and "/64" (as the subnet prefix length) to the right.

edited Mar 01 '12 at 14:13

Mark Ursino

31,209
11
51
83

answered Mar 01 '12 at 08:21

sleinen

511
3
10

Thanks. I'll take this approach for now. – Maddy Mar 05 '12 at 10:27
5

You can automatically derive the link local address with `$ ipv6calc --in prefix+mac fe80:: $MACADDR` – maxschlepzig Jan 29 '17 at 15:59
Or just set it to fe80::1? – TJJ Mar 23 '21 at 22:12

Adding link local address

1 Answers1