[PATCH net] ipv6: addrconf: reduce default temp_valid_lft to 2 days

[PATCH net] ipv6: addrconf: reduce default temp_valid_lft to 2 days

[Fernando Fernandez Mancera]

This is a recommendation from RFC 8981 and it was intended to be changed
by commit 969c54646af0 ("ipv6: Implement draft-ietf-6man-rfc4941bis")
but it only changed the sysctl documentation.

Fixes: 969c54646af0 ("ipv6: Implement draft-ietf-6man-rfc4941bis")
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
---
 include/net/addrconf.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 78e8b877fb25..e9511df721c6 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -8,7 +8,7 @@
 
 #define MIN_VALID_LIFETIME		(2*3600)	/* 2 hours */
 
-#define TEMP_VALID_LIFETIME		(7*86400)       /* 1 week */
+#define TEMP_VALID_LIFETIME		(2*86400)       /* 2 days */
 #define TEMP_PREFERRED_LIFETIME		(86400)         /* 24 hours */
 #define REGEN_MIN_ADVANCE		(2)             /* 2 seconds */
 #define REGEN_MAX_RETRY			(3)
-- 
2.52.0

Re: [PATCH net] ipv6: addrconf: reduce default temp_valid_lft to 2 days

[Simon Horman]

On Wed, Feb 11, 2026 at 09:20:03PM +0100, Fernando Fernandez Mancera wrote:
> This is a recommendation from RFC 8981 and it was intended to be changed
> by commit 969c54646af0 ("ipv6: Implement draft-ietf-6man-rfc4941bis")
> but it only changed the sysctl documentation.
> 
> Fixes: 969c54646af0 ("ipv6: Implement draft-ietf-6man-rfc4941bis")
> Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>

Reviewed-by: Simon Horman <horms@kernel.org>

Re: [PATCH net] ipv6: addrconf: reduce default temp_valid_lft to 2 days

[Eric Dumazet]

On Fri, Feb 13, 2026 at 3:00 PM Simon Horman <horms@kernel.org> wrote:
>
> On Wed, Feb 11, 2026 at 09:20:03PM +0100, Fernando Fernandez Mancera wrote:
> > This is a recommendation from RFC 8981 and it was intended to be changed
> > by commit 969c54646af0 ("ipv6: Implement draft-ietf-6man-rfc4941bis")
> > but it only changed the sysctl documentation.
> >
> > Fixes: 969c54646af0 ("ipv6: Implement draft-ietf-6man-rfc4941bis")
> > Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
>
> Reviewed-by: Simon Horman <horms@kernel.org>


I would recommend adding a comment, because final RFC states
"TEMP_VALID_LIFETIME -- Default value: 1 week. Users should be able
to override the default value.

https://datatracker.ietf.org/doc/html/rfc4941#section-5

So... do we still need a different value in linux, and why ?

Re: [PATCH net] ipv6: addrconf: reduce default temp_valid_lft to 2 days

[Fernando Fernandez Mancera]

On 2/13/26 3:34 PM, Eric Dumazet wrote:
> On Fri, Feb 13, 2026 at 3:00 PM Simon Horman <horms@kernel.org> wrote:
>>
>> On Wed, Feb 11, 2026 at 09:20:03PM +0100, Fernando Fernandez Mancera wrote:
>>> This is a recommendation from RFC 8981 and it was intended to be changed
>>> by commit 969c54646af0 ("ipv6: Implement draft-ietf-6man-rfc4941bis")
>>> but it only changed the sysctl documentation.
>>>
>>> Fixes: 969c54646af0 ("ipv6: Implement draft-ietf-6man-rfc4941bis")
>>> Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
>>
>> Reviewed-by: Simon Horman <horms@kernel.org>
> 
> 
> I would recommend adding a comment, because final RFC states
> "TEMP_VALID_LIFETIME -- Default value: 1 week. Users should be able
> to override the default value.
> 
> https://datatracker.ietf.org/doc/html/rfc4941#section-5
> 
> So... do we still need a different value in linux, and why ?
> 

RFC 8981 obsoletes RFC 4941, the new RFC states
"TEMP_VALID_LIFETIME -- Default value: 2 days. Users should be able to 
override the default value."

https://datatracker.ietf.org/doc/html/rfc8981#section-3.8

I didn't include the reasoning because it was already on the blamed 
commit which comes from the RFC 8981 too.

https://datatracker.ietf.org/doc/html/rfc8981#section-4

Anyway, I am fine adding a comment or mentioning it on the commit 
message if needed.

Thanks,
Fernando.

Re: [PATCH net] ipv6: addrconf: reduce default temp_valid_lft to 2 days

[Fernando Fernandez Mancera]

On 2/13/26 3:44 PM, Fernando Fernandez Mancera wrote:
> On 2/13/26 3:34 PM, Eric Dumazet wrote:
>> On Fri, Feb 13, 2026 at 3:00 PM Simon Horman <horms@kernel.org> wrote:
>>>
>>> On Wed, Feb 11, 2026 at 09:20:03PM +0100, Fernando Fernandez Mancera 
>>> wrote:
>>>> This is a recommendation from RFC 8981 and it was intended to be 
>>>> changed
>>>> by commit 969c54646af0 ("ipv6: Implement draft-ietf-6man-rfc4941bis")
>>>> but it only changed the sysctl documentation.
>>>>
>>>> Fixes: 969c54646af0 ("ipv6: Implement draft-ietf-6man-rfc4941bis")
>>>> Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
>>>
>>> Reviewed-by: Simon Horman <horms@kernel.org>
>>
>>
>> I would recommend adding a comment, because final RFC states
>> "TEMP_VALID_LIFETIME -- Default value: 1 week. Users should be able
>> to override the default value.
>>
>> https://datatracker.ietf.org/doc/html/rfc4941#section-5
>>
>> So... do we still need a different value in linux, and why ?
>>
> 
> RFC 8981 obsoletes RFC 4941, the new RFC states
> "TEMP_VALID_LIFETIME -- Default value: 2 days. Users should be able to 
> override the default value."
> 
> https://datatracker.ietf.org/doc/html/rfc8981#section-3.8
> 
> I didn't include the reasoning because it was already on the blamed 
> commit which comes from the RFC 8981 too.
> 
> https://datatracker.ietf.org/doc/html/rfc8981#section-4
> 
> Anyway, I am fine adding a comment or mentioning it on the commit 
> message if needed.
> 

I noticed the patch is marked as "Changes Requested", is there some 
action pending from me?

Thanks,
Fernando.

Re: [PATCH net] ipv6: addrconf: reduce default temp_valid_lft to 2 days

[Eric Dumazet]

On Sat, Feb 14, 2026 at 2:28 PM Fernando Fernandez Mancera
<fmancera@suse.de> wrote:

> I noticed the patch is marked as "Changes Requested", is there some
> action pending from me?

Quite confusing. The blamed commit mentioned RFC 4941

commit 969c54646af0d7d94a5f0f37adbbfe024e85466e
Author: Fernando Gont <fgont@si6networks.com>
Date:   Fri May 1 00:51:47 2020 -0300

    ipv6: Implement draft-ietf-6man-rfc4941bis

So please add a comment like this one ?

/* TEMP_VALID_LIFETIME default value as specified in RFC 8981 3.8 */

Thank you.

Re: [PATCH net] ipv6: addrconf: reduce default temp_valid_lft to 2 days

[Fernando Fernandez Mancera]

On 2/14/26 2:37 PM, Eric Dumazet wrote:
> On Sat, Feb 14, 2026 at 2:28 PM Fernando Fernandez Mancera
> <fmancera@suse.de> wrote:
> 
>> I noticed the patch is marked as "Changes Requested", is there some
>> action pending from me?
> 
> Quite confusing. The blamed commit mentioned RFC 4941
> 
> commit 969c54646af0d7d94a5f0f37adbbfe024e85466e
> Author: Fernando Gont <fgont@si6networks.com>
> Date:   Fri May 1 00:51:47 2020 -0300
> 
>      ipv6: Implement draft-ietf-6man-rfc4941bis
> 
> So please add a comment like this one ?
> 
> /* TEMP_VALID_LIFETIME default value as specified in RFC 8981 3.8 */
> 

Sure, I will. FWIW, the blamed commit mentioned the draft revision for 
RFC 4941, but at that time, being a draft, it did not have an 
appropriate RFC number assigned to it.

Thanks Eric.

Re: [PATCH net] ipv6: addrconf: reduce default temp_valid_lft to 2 days

[Fernando Gont]

On 14/2/26 10:43, Fernando Fernandez Mancera wrote:
> On 2/14/26 2:37 PM, Eric Dumazet wrote:
>> On Sat, Feb 14, 2026 at 2:28 PM Fernando Fernandez Mancera
>> <fmancera@suse.de> wrote:
>>
>>> I noticed the patch is marked as "Changes Requested", is there some
>>> action pending from me?
>>
>> Quite confusing. The blamed commit mentioned RFC 4941
>>
>> commit 969c54646af0d7d94a5f0f37adbbfe024e85466e
>> Author: Fernando Gont <fgont@si6networks.com>
>> Date:   Fri May 1 00:51:47 2020 -0300
>>
>>      ipv6: Implement draft-ietf-6man-rfc4941bis
>>
>> So please add a comment like this one ?
>>
>> /* TEMP_VALID_LIFETIME default value as specified in RFC 8981 3.8 */
>>
> 
> Sure, I will. FWIW, the blamed commit mentioned the draft revision for 
> RFC 4941, but at that time, being a draft, it did not have an 
> appropriate RFC number assigned to it.

Note: the commit referenced the right filename: IETF draft 
draft-ietf-6man-rfc4941bis. -- IETF drafts that are meant to revise an 
existing RFC codify such RFC number in the filename (e.g., this draft 
had "rfc4941bis" in the filename because, when published as an RFC, it 
would formally revise RFC4941).

Thanks,
-- 
Fernando Gont
SI6 Networks
e-mail: fgont@si6networks.com
PGP Fingerprint: F242 FF0E A804 AF81 EB10 2F07 7CA1 321D 663B B494