Mailing List Archive: ip switching from ipv4 to ipv6

ip switching from ipv4 to ipv6

Apr 29, 2016, 5:46 AM

Post #1 of 8 (2962 views)

dear ipv6-ops list members,

one of our users is unable to login to webmail, because the ip address is
changing during session. this problem isnt that unusual, but after a check
in the logfiles i realized its switching from ipv4 to ipv6 and so on, (see below).

is this phenomenon known?
is it us or the deutsche telekom who is causing the problem?

thanks in advance,
re - noc.mur.at

#####

Apr 29 09:54:34 dovecot: imap-login: Login: user=<>, method=PLAIN,
rip=217.233.160.66

Apr 29 09:57:54 dovecot: imap-login: Login: user=<>, method=PLAIN,
rip=2003:88:6c55:4707:b538:efe9:d4fb:bdf7

Apr 29 10:05:17 dovecot: imap-login: Login: user=<>, method=PLAIN,
rip=217.233.160.66

Apr 29 10:05:19 dovecot: imap-login: Login: user=<>, method=PLAIN,
rip=2003:88:6c55:4707:b538:efe9:d4fb:bdf7

Apr 29 11:29:03 dovecot: imap-login: Login: user=<>, method=PLAIN,
rip=217.233.160.66

Apr 29 11:45:09 dovecot: imap-login: Login: user=<>, method=PLAIN,
rip=2003:88:6c55:4707:b538:efe9:d4fb:bdf7

--
--mur.at leitnergasse 7-12 8010 graz--

Re: ip switching from ipv4 to ipv6 [ In reply to ]

Apr 29, 2016, 5:49 AM

Post #2 of 8 (2944 views)

It could well be Happy Eyeballs. One more reason to curtail (or
eliminate) IP-based auth.

On 29 April 2016 at 21:46, re <re-tech@mur.at> wrote:
> dear ipv6-ops list members,
>
> one of our users is unable to login to webmail, because the ip address is
> changing during session. this problem isnt that unusual, but after a check
> in the logfiles i realized its switching from ipv4 to ipv6 and so on, (see below).
>
> is this phenomenon known?
> is it us or the deutsche telekom who is causing the problem?
>
> thanks in advance,
> re - noc.mur.at
>
> #####
>
> Apr 29 09:54:34 dovecot: imap-login: Login: user=<>, method=PLAIN,
> rip=217.233.160.66
>
> Apr 29 09:57:54 dovecot: imap-login: Login: user=<>, method=PLAIN,
> rip=2003:88:6c55:4707:b538:efe9:d4fb:bdf7
>
> Apr 29 10:05:17 dovecot: imap-login: Login: user=<>, method=PLAIN,
> rip=217.233.160.66
>
> Apr 29 10:05:19 dovecot: imap-login: Login: user=<>, method=PLAIN,
> rip=2003:88:6c55:4707:b538:efe9:d4fb:bdf7
>
> Apr 29 11:29:03 dovecot: imap-login: Login: user=<>, method=PLAIN,
> rip=217.233.160.66
>
> Apr 29 11:45:09 dovecot: imap-login: Login: user=<>, method=PLAIN,
> rip=2003:88:6c55:4707:b538:efe9:d4fb:bdf7
>
> --
> --mur.at leitnergasse 7-12 8010 graz--

Re: ip switching from ipv4 to ipv6 [ In reply to ]

evyncke at cisco

Apr 29, 2016, 5:50 AM

Post #3 of 8 (2945 views)

See also
https://tools.ietf.org/html/draft-vyncke-v6ops-happy-eyeballs-cookie-01

Kind of a well-known problem when "naive" applications/CMS/middleware
trust an IP address to protect cookies

-Ã©ric

On 29/04/16 14:46, "ipv6-ops-bounces+evyncke=cisco.com@lists.cluenet.de on
behalf of re" <ipv6-ops-bounces+evyncke=cisco.com@lists.cluenet.de on
behalf of re-tech@mur.at> wrote:

>dear ipv6-ops list members,
>
>one of our users is unable to login to webmail, because the ip address is
>changing during session. this problem isnt that unusual, but after a check
>in the logfiles i realized its switching from ipv4 to ipv6 and so on,
>(see below).
>
>is this phenomenon known?
>is it us or the deutsche telekom who is causing the problem?
>
>thanks in advance,
>re - noc.mur.at
>
>#####
>
>Apr 29 09:54:34 dovecot: imap-login: Login: user=<>, method=PLAIN,
>rip=217.233.160.66
>
>Apr 29 09:57:54 dovecot: imap-login: Login: user=<>, method=PLAIN,
>rip=2003:88:6c55:4707:b538:efe9:d4fb:bdf7
>
>Apr 29 10:05:17 dovecot: imap-login: Login: user=<>, method=PLAIN,
>rip=217.233.160.66
>
>Apr 29 10:05:19 dovecot: imap-login: Login: user=<>, method=PLAIN,
>rip=2003:88:6c55:4707:b538:efe9:d4fb:bdf7
>
>Apr 29 11:29:03 dovecot: imap-login: Login: user=<>, method=PLAIN,
>rip=217.233.160.66
>
>Apr 29 11:45:09 dovecot: imap-login: Login: user=<>, method=PLAIN,
>rip=2003:88:6c55:4707:b538:efe9:d4fb:bdf7
>
>--
>--mur.at leitnergasse 7-12 8010 graz--

Re: ip switching from ipv4 to ipv6 [ In reply to ]

Apr 29, 2016, 6:08 AM

Post #4 of 8 (2945 views)

On Fri, 29 Apr 2016, re wrote:

> is it us or the deutsche telekom who is causing the problem?

This isn't a problem, this is expected behavior.

Don't trust the IP address to be stable, at least not between IPv4/IPv6.

--
Mikael Abrahamsson email: swmike@swm.pp.se

Re: ip switching from ipv4 to ipv6 [ In reply to ]

Apr 29, 2016, 6:09 AM

Post #5 of 8 (2945 views)

> See also
> https://tools.ietf.org/html/draft-vyncke-v6ops-happy-eyeballs-cookie-01

thanks to both of you!
i ll dig into horde config if there is another possibility of saving the session
state.

but is there any explanation to the repeated changing of the ip address from ipv4
to ipv6?

thanks!
re
--
--mur.at leitnergasse 7-12 8010 graz--

Re: ip switching from ipv4 to ipv6 [ In reply to ]

Apr 29, 2016, 6:16 AM

Post #6 of 8 (2945 views)

On Fri, 29 Apr 2016, re wrote:

> but is there any explanation to the repeated changing of the ip address
> from ipv4 to ipv6?

https://en.wikipedia.org/wiki/Happy_Eyeballs

If network conditions change then IPv4 or IPv6 might be preferred over
time. It'll usually give a little bit of head-start for IPv6 (depending on
implementation), but if v6 is significantly worse parts of the time, then
you'll see the client bouncing between versions.

--
Mikael Abrahamsson email: swmike@swm.pp.se

Re: ip switching from ipv4 to ipv6 [ In reply to ]

Apr 29, 2016, 6:24 AM

Post #7 of 8 (2940 views)

I suppose you could just inject 300-500ms latency on IPv4 connections
somehow. That might "fitch the glitch". =)

On 29 April 2016 at 22:16, Mikael Abrahamsson <swmike@swm.pp.se> wrote:
> On Fri, 29 Apr 2016, re wrote:
>
>> but is there any explanation to the repeated changing of the ip address
>> from ipv4 to ipv6?
>
>
> https://en.wikipedia.org/wiki/Happy_Eyeballs
>
> If network conditions change then IPv4 or IPv6 might be preferred over time.
> It'll usually give a little bit of head-start for IPv6 (depending on
> implementation), but if v6 is significantly worse parts of the time, then
> you'll see the client bouncing between versions.
>
>
> --
> Mikael Abrahamsson email: swmike@swm.pp.se

Re: ip switching from ipv4 to ipv6 [ In reply to ]

brian.e.carpenter at gmail

Apr 29, 2016, 1:10 PM

Post #8 of 8 (2931 views)

On 30/04/2016 01:16, Mikael Abrahamsson wrote:
> On Fri, 29 Apr 2016, re wrote:
>
>> but is there any explanation to the repeated changing of the ip address from ipv4 to ipv6?
>
> https://en.wikipedia.org/wiki/Happy_Eyeballs
>
> If network conditions change then IPv4 or IPv6 might be preferred over time. It'll usually give a little bit of head-start for
> IPv6 (depending on implementation), but if v6 is significantly worse parts of the time, then you'll see the client bouncing
> between versions.
>

And look for the relevant browser option to switch it off. For Firefox it
seems to need network.http.fast-fallback-to-IPv4;false

Brian