Jeremie, thank for paying attention to my post and explanation.
Finally I found that 0x58 (0x18 + 0x64) or :raflags#88: did what I
wanted - Other flag set and Default Router Preference set to Low (3).
Internet Control Message Protocol v6
Type: Router Advertisement (134)
Code: 0
Checksum: 0x06ee [correct]
Cur hop limit: 64
Flags: 0x58
0... .... = Managed address configuration: Not set
.1.. .... = Other configuration: Set
..0. .... = Home Agent: Not set
...1 1... = Prf (Default Router Preference): Low (3)
.... .0.. = Proxy: Not set
.... ..0. = Reserved: 0
Router lifetime (s): 1800
Reachable time (ms): 0
Retrans timer (ms): 0
As I see you also committed some changes to rtadvd.conf today, thank you again.
--
Evgeniy
On Wed, May 4, 2016 at 9:36 PM, Jeremie Courreges-Anglas <[email protected]>
wrote:
> Evgeniy Sudyr <[email protected]> writes:
>
>> Hi,
>>
>> I want to change route preference for the default route in RA messages
>> which are sent to clients.
>>
>> On 5.9 GENERIC.MP#1888 amd64 I do have rtadvd and changing rtflags in
>> rtadvd.conf doesn't changes
>>
>> Default router Preference (it sends default value, where I define "l" = Low).
>>
>> In config I have just two items set:
>>
>> vlan6:\
>> :raflags#64:\
>> :rtflags="l":
>>
>> raflags#64 (Other stateful configuration flag bit)
>> rtflags="l" (Low route preference for the route)
>
> I don't understand what "l" means here, rtadvd.conf(5) doesn't seem to
> mention this as a valid setting.
>
>> I'm always getting pref=medium for default router preference.
>>
>> $ ndp -rn
>> fe80::xxxx:xxxx:xxxx:5e0c%vlan0 if=vlan0, flags=O, pref=medium, expire=29m52s
>>
>> However It works perfect for non-default route preference for the
>> route, but not default e.g.:
>>
>> vlan6:\
>> :raflags#64:rtflags="l":rtprefix="2001:1:1:1::":rtplen#64:
>>
>> It will be great if someone can share working config options which
>> allows to change DRFAULT router preference RA message value.
>
> As the rtflags description says, bits 4 and 3 are used to encode the
> preference. "low" is 0x18 / 24. :raflags#24: seems to do the trick
> here.
>
> Your mail points out three problems imo:
> - tcpdump doesn't show the preference
> - the documentation of raflags is lacking
> - it's a shame that raflags was used instead of a nicer config
> abstraction. I think :pref="low":managed#1: would be a bit easier
> than playing with... bits.
>
> --
> jca | PGP : 0x1524E7EE / 5135 92C1 AD36 5293 2BDF DDCC 0DFA 74AE 1524 E7EE
--
--
With regards,
Eugene Sudyr
