dhcpcd-discuss

Hi Renu

Sorry for the late rely

On 27/06/2017 12:18, Renu Bansal wrote:
> I have upgraded dhcp client to dhcpcd-7.0.0-rc1. I am using default dhcpcd.conf file
> According to my current network configuration M bit is disabled and O bit is set.
> 
> Please check below the Router advertisement packet:
> --------------------------------------------------------------------------XX-----------------------------------------------------------------------
> Internet Control Message Protocol v6
>     Type: Router Advertisement (134)
>     Code: 0
>     Checksum: 0x93b0 [correct]
>     [Checksum Status: Good]
>     Cur hop limit: 64
>     Flags: 0x40
>         0... .... = Managed address configuration: Not set
>         .1.. .... = Other configuration: Set
>         ..0. .... = Home Agent: Not set
>         ...0 0... = Prf (Default Router Preference): Medium (0)
>         .... .0.. = Proxy: Not set
>         .... ..0. = Reserved: 0
>     Router lifetime (s): 1800
>     Reachable time (ms): 0
>     Retrans timer (ms): 0
>     ICMPv6 Option (Source link-layer address : 30:8d:99:33:70:00)
>     ICMPv6 Option (Prefix information : 2017::/64)

So based on this, dhcpcd should not attempt to solicit any addresses.

> --------------------------------------------------------------------XX------------------------------------------------------------
> Dhcpcd replies with following solicit message:
> -----------------------------------------------------------XX------------------------------------------------------------------------
> DHCPv6
>     Message type: Solicit (1)
>     Transaction ID: 0x83a3ef
>     Client Identifier
>     Elapsed time
>     Vendor Class
>     Identity Association for Non-temporary Address
>         Option: Identity Association for Non-temporary Address (3)
>         Length: 12
>         Value: b9a707ff0000000000000000
>         IAID: b9a707ff
>         T1: 0
>         T2: 0
>     Identity Association for Prefix Delegation
>     Fully Qualified Domain Name
>     Reconfigure Accept
>     Option Request
> ------------------------------------------------------XX----------------------------------------------------------------------
> This implies dhcpcd client do not omits " IANA" field and hence I am getting IPv6 address from dhcpv6 server.
> Do you think this could be due to older linux kernel version. Could you suggest if any linux patch might resolve this issue.
> 
> Can you suggest some configuration or sample dhcpcd.conf file which can support stateless dhcp configuration.

The stock dhcpcd.conf does not request any Prefix Delegation.
Also, it sets the Rapid Commit option, which is missing from the above.

So one of these two statements must be true:
   1)   dhcpcd is not using the stock dhcpcd.conf
   2)   That solicit message didn't come from dhcpcd

Saying that, dhcpcd has broken (depending on DHCPv6 server) inform
support in -7.x which is fixed here:
https://dev.marples.name/rDHC0a71632353de8a50f9ac15cb6d27e57fc0a4c516

Roy