Opened 3 months ago

Last modified 2 weeks ago

#1282 new Bug / Defect

No IPv6 connectivity if client gets assigned the first IP of the /64 block

Reported by: NicolaF_ Owned by: Gert Döring
Priority: major Milestone: release 2.4.7
Component: IPv6 Version:
Severity: Not set (select this one, unless your'e a OpenVPN developer) Keywords:



With the attached server configuration, if a client gets assigned the fitst IPv6 of the 64 block, ie. <VPN ipv6 prefix>::0 , it has not IPv6 connectivity. Packets gets lost. He gets the first IPv4 too (, .0 in ipp.txt), but IPv6 works fine.

Strangely enough, the incriminated IPv6 responds to ping even if no client is connected:

root@OpenWrt:~# ping <VPN ipv6 prefix>::
PING <VPN ipv6 prefix>:: (<VPN ipv6 prefix>::): 56 data bytes
64 bytes from <VPN ipv6 prefix>::254: seq=0 ttl=64 time=0.377 ms
64 bytes from <VPN ipv6 prefix>::254: seq=1 ttl=64 time=0.262 ms
64 bytes from <VPN ipv6 prefix>::254: seq=2 ttl=64 time=0.257 ms
64 bytes from <VPN ipv6 prefix>::254: seq=3 ttl=64 time=0.261 ms
--- <VPN ipv6 prefix>:: ping statistics ---
4 packets transmitted, 4 packets received, 0% packet loss
round-trip min/avg/max = 0.257/0.289/0.377 ms

Workaround: add a dummy entry in ipp.txt to ensure that no client gets the first IP


Attachments (1)

server.conf (969 bytes) - added by NicolaF_ 3 months ago.
Server configuration

Download all attachments as: .zip

Change History (3)

Changed 3 months ago by NicolaF_

Attachment: server.conf added

Server configuration

comment:1 Changed 3 months ago by NicolaF_

Typo: but IPv6 works fine -> but IPv4 works fine

comment:2 Changed 2 weeks ago by tincantech

Looks like it depends on this:

ifconfig-ipv6-pool <VPN ipv6 prefix>::/64

Last edited 2 weeks ago by tincantech (previous) (diff)
Note: See TracTickets for help on using tickets.