Hi all, I’m wondering if I’m understanding this correctly and if so, if it is a good practice. In email mesases received from IONOS, I see in the header: X-Received: by 2002:ac8:5ac5:0:b0:46d:fd08:7c9f with SMTP id d75a77b69052e-46e12a462a7mr251941861cf.22.1737462364476; Tue, 21 Jan 2025 04:26:04 -0800 (PST) Another example: X-Received: by 2002:a05:622a:38b:b0:46c:7646:4a1e with SMTP id d75a77b69052e-46e12a62966mr243715391cf.13.1737416130721; Mon, 20 Jan 2025 15:35:30 -0800 (PST) It looks to me like they are using 2002 as the IPv6 address of the email for the client hosted mail/domains? Regards, Jordi @jordipalet ********************************************** IPv4 is over Are you ready for the new Internet ? http://www.theipv6company.com The IPv6 Company This electronic message contains information which may be privileged or confidential. The information is intended to be for the exclusive use of the individual(s) named above and further non-explicilty authorized disclosure, copying, distribution or use of the contents of this information, even if partially, including attached files, is strictly prohibited and will be considered a criminal offense. If you are not the intended recipient be aware that any disclosure, copying, distribution or use of the contents of this information, even if partially, including attached files, is strictly prohibited, will be considered a criminal offense, so you must reply to the original sender to inform about this communication and delete it.
Unfortunately, they are not the only one with that bad practice. Google does too, for a long time already. (different service mails) This is an example from last security warning X-Received: by 2002:a05:6602:4742:b0:83a:a82b:f856 with SMTP id ... Thomas Am 21.01.25 um 14:38 schrieb Jordi Palet Martinez via ipv6-wg:
Hi all,
I’m wondering if I’m understanding this correctly and if so, if it is a good practice.
In email mesases received from IONOS, I see in the header:
X-Received: by 2002:ac8:5ac5:0:b0:46d:fd08:7c9f with SMTP id d75a77b69052e-46e12a462a7mr251941861cf.22.1737462364476; Tue, 21 Jan 2025 04:26:04 -0800 (PST)
Another example:
X-Received: by 2002:a05:622a:38b:b0:46c:7646:4a1e with SMTP id d75a77b69052e-46e12a62966mr243715391cf.13.1737416130721; Mon, 20 Jan 2025 15:35:30 -0800 (PST)
It looks to me like they are using 2002 as the IPv6 address of the email for the client hosted mail/domains?
Didn’t knew they also do it. Really ugly (I might use a much worst wording if not a public list). Regards, Jordi @jordipalet
El 21 ene 2025, a las 15:54, Thomas Schäfer <tschaefer@t-online.de> escribió:
Unfortunately, they are not the only one with that bad practice. Google does too, for a long time already. (different service mails)
This is an example from last security warning
X-Received: by 2002:a05:6602:4742:b0:83a:a82b:f856 with SMTP id ...
Thomas
Am 21.01.25 um 14:38 schrieb Jordi Palet Martinez via ipv6-wg:
Hi all, I’m wondering if I’m understanding this correctly and if so, if it is a good practice. In email mesases received from IONOS, I see in the header: X-Received: by 2002:ac8:5ac5:0:b0:46d:fd08:7c9f with SMTP id d75a77b69052e-46e12a462a7mr251941861cf.22.1737462364476; Tue, 21 Jan 2025 04:26:04 -0800 (PST) Another example: X-Received: by 2002:a05:622a:38b:b0:46c:7646:4a1e with SMTP id d75a77b69052e-46e12a62966mr243715391cf.13.1737416130721; Mon, 20 Jan 2025 15:35:30 -0800 (PST) It looks to me like they are using 2002 as the IPv6 address of the email for the client hosted mail/domains?
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********************************************** IPv4 is over Are you ready for the new Internet ? http://www.theipv6company.com The IPv6 Company This electronic message contains information which may be privileged or confidential. The information is intended to be for the exclusive use of the individual(s) named above and further non-explicilty authorized disclosure, copying, distribution or use of the contents of this information, even if partially, including attached files, is strictly prohibited and will be considered a criminal offense. If you are not the intended recipient be aware that any disclosure, copying, distribution or use of the contents of this information, even if partially, including attached files, is strictly prohibited, will be considered a criminal offense, so you must reply to the original sender to inform about this communication and delete it.
Am Tue, 21 Jan 2025 14:38:44 +0100 schrieb Jordi Palet Martinez via ipv6-wg <ipv6-wg@ripe.net>:
X-Received: by 2002:ac8:5ac5:0:b0:46d:fd08:7c9f with SMTP id d75a77b69052e-46e12a462a7mr251941861cf.22.1737462364476; Tue, 21 Jan 2025 04:26:04 -0800 (PST)
6to4 with private IPv4 address in the inside. Cannot be used in in the internet, but inside the internal network. I don't see any problem here.
Hi, On Tue, Jan 21, 2025 at 04:03:53PM +0100, Marco Moock wrote:
6to4 with private IPv4 address in the inside.
I don't see any problem here.
Why would anyone do this? If you only have v4, use v4, not pretend to have v6. If you have real v6, do not use 2002: Gert Doering -- NetMaster -- have you enabled IPv6 on something today...? SpaceNet AG Vorstand: Sebastian v. Bomhard, Ingo Lalla, Karin Schuler, Sebastian Cler Joseph-Dollinger-Bogen 14 Aufsichtsratsvors.: A. Grundner-Culemann D-80807 Muenchen HRB: 136055 (AG Muenchen) Tel: +49 (0)89/32356-444 USt-IdNr.: DE813185279
Exactly, that was my point: the 6to4 address 2002:ac8:5ac5:0:b0:46d:fd08:7c9f actually means that the originator is 10.200.90.197 (ac8:5ac5). Being a private address I don’t think it is valid as a 6to4 address source, because they are meant for public IPv4 addresses: The document defines a method for assigning an interim unique IPv6 address prefix to any site that currently has at least one globally unique IPv4 address, and specifies an encapsulation mechanism for transmitting IPv6 packets using such a prefix over the global IPv4 network. It seems to me is generated by IONOS/Kundenserver. It looks to me like they are using internal email servers for customers and instead of properly configuring IPv6, they allow 6to4 addresses to be generated or may be they do it on purpose. The interesting thing is that afterwards they send the email via IPv4 only! So either you configure IPv6 properly all the way thru, or not at all, but this way using an invalid 6to4 address is very weird and definitively not a good practice. May be someone has contact with them so they realize this is broken. Regards, Jordi @jordipalet
El 21 ene 2025, a las 19:19, Gert Doering <gert@space.net> escribió:
Hi,
On Tue, Jan 21, 2025 at 04:03:53PM +0100, Marco Moock wrote:
6to4 with private IPv4 address in the inside.
I don't see any problem here.
Why would anyone do this?
If you only have v4, use v4, not pretend to have v6. If you have real v6, do not use 2002:
Gert Doering -- NetMaster -- have you enabled IPv6 on something today...?
SpaceNet AG Vorstand: Sebastian v. Bomhard, Ingo Lalla, Karin Schuler, Sebastian Cler Joseph-Dollinger-Bogen 14 Aufsichtsratsvors.: A. Grundner-Culemann D-80807 Muenchen HRB: 136055 (AG Muenchen) Tel: +49 (0)89/32356-444 USt-IdNr.: DE813185279 ----- To unsubscribe from this mailing list or change your subscription options, please visit: https://mailman.ripe.net/mailman3/lists/ipv6-wg.ripe.net/ As we have migrated to Mailman 3, you will need to create an account with the email matching your subscription before you can change your settings. More details at: https://www.ripe.net/membership/mail/mailman-3-migration/
********************************************** IPv4 is over Are you ready for the new Internet ? http://www.theipv6company.com The IPv6 Company This electronic message contains information which may be privileged or confidential. The information is intended to be for the exclusive use of the individual(s) named above and further non-explicilty authorized disclosure, copying, distribution or use of the contents of this information, even if partially, including attached files, is strictly prohibited and will be considered a criminal offense. If you are not the intended recipient be aware that any disclosure, copying, distribution or use of the contents of this information, even if partially, including attached files, is strictly prohibited, will be considered a criminal offense, so you must reply to the original sender to inform about this communication and delete it.
participants (4)
-
Gert Doering -
jordi.palet＠consulintel.es -
Marco Moock -
Thomas Schäfer