[123attendees] Re: Issues with IPv4 address instability - only for people from Netherlands?

[Warren Kumari <[e-mail]>]

 Yeah, that's my fault.

This is working as intended... but the intent may have been incorrect :-p

The IETF network is unusual in that it lies dormant for around 4 months,
and then comes alive for a week, and then goes dormant again. This means
that some CDNs become startled by the zombies, and block list individual
IPs.

I decided to not make the NAT mapping deterministic ("address-persistent"
or "persistent-nat), so that if a CDN did this, the user could just refresh
their (almost definitely) browser page and would get a new address.

Almost all sites have moved away from IP addresses "verification" because
of things like multiple connections (WiFi and Cellular), CGNs, etc., but it
looks like this might have caused more issues than it helped... I believe
that the NOC is planning on twiddling the knob during tear down to test the
persistence behavior and may be persistent in Montreal...

Warren


On Wed, Jul 23, 2025 at 8:15 PM, Benfeng Chen <[e-mail]> wrote:

> I am seeing the same issue of IPv4 address instability.  With the same
> computer and the same browser, I saw different IPv4 addresses on different
> websites. If I refresh, the IP address changes to another one.
> [image: image.png]
> [image: image.png]
>
> [image: image.png]
>
>
>
> On Wed, Jul 23, 2025 at 7:28 PM Ondřej Caletka <[e-mail]>
> wrote:
>
>> Hey,
>>
>> I reported yesterday that the default network called ietf has issues
>> with some IPv4-only websites due to the fact that the current setup of
>> NAT64 maps each individual session to possibly different IPv4
>> addresses. You can see it by opening your favourite "What is my IPv4"
>> website and refreshing the browser a few times.
>>
>> This does not present a problem for most services, but there are some
>> websites whose authors didn't expect that a single user behind a
>> single browser can be accessing the web server from several IPv4
>> addresses. Typical cases are DRM protected video-on-demand websites
>> where the browser first asks for a license and this license/token is
>> then valid only for the IPv4 address from which it was requested.
>>
>> An example of such a website is https://nos.nl/l/2576078 but I also
>> noticed that HR software called AFAS Insite gets completely broken in
>> such a situation.
>> Since I have a theory that users tend to suffer in silence, I would
>> like to gauge if I am really the only one noticing this or if there is
>> anyone else who spotted something not working as usual but considered
>> it too minor to report. Please report broken websites (possibly also
>> to the owners of those websites.)
>>
>> --
>> Best regards,
>> Ondřej Caletka
>>
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