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DHCPv6-PD add prefix hint CLI option
Closed, ResolvedPublicFEATURE REQUEST


Some ISPs (e.g. Comcast in Australia) only delegate a /64 by default. You have to explicitly ask for a /60 prefix (see discussion in T421).

Add CLI node to „help“ the dhcp client to request an appropriate size.


Difficulty level
Normal (likely a few hours)
Why the issue appeared?
Will be filled on close
Is it a breaking change?
Unspecified (possibly destroys the router)
Issue type
Feature (new functionality)

Event Timeline

c-po triaged this task as Normal priority.
c-po created this task.
c-po changed Difficulty level from Unknown (require assessment) to Easy (less than an hour).

Guess the CLI needs a change here as this requirement was overseen. It could look something like this (note that PPPoE can be replaced by any other interface), need to work out the details.

+pppoe pppoe0 {
+    authentication {
+        password vyos
+        user vyos
+    }
+    dhcpv6-options {
+        prefix-delegation {
+            interface eth1 {
+                address 1
+                sla-id 0
+                sla-len 5
+            }
+            length 60
+        }
+    }
+    ipv6 {
+        address {
+            autoconf
+        }
+        enable
+    }
+    mtu 1400
+    source-interface eth0.202
+    vrf black

I‘m asking myself if length should be specified as decimal number or as ::/60 prefix?

If this field is only the len, of prefix, there is no need to use prefix writing.

c-po changed the task status from Open to In progress.May 26 2020, 3:11 PM
c-po changed Difficulty level from Easy (less than an hour) to Normal (likely a few hours).
erkin set Issue type to Feature (new functionality).Aug 30 2021, 6:01 AM
erkin removed a subscriber: Active contributors.