One of the machines that I run my sinkhole SMTP server on has an IPv6 address, one that's currently present in DNS as the target of an MX record (not literally, of course, it's the AAAA record of the host that's the MX target). Back in October, in a somewhat different DNS setup, it saw its first IPv6 probe, and has seen a number since then. A bit over a week ago it got its first actual spam email over IPv6.

The source IPv6 address is in Asia, which doesn't surprise me; my impression is that APNIC is one of the most active areas for IPv6 usage for various reasons (including IPv4 address exhaustion). The sending host appears to also have an IPv4 address, but apparently it prefers to use IPv6 if it can (which is again not surprising). Its IPv4 address is listed in a couple of DNS blocklists, including b.barracudacentral.org, but is not in Spamhaus or the CBL.

(Spamhaus has an old policy statement about IPv6 that gives an example of querying them for IPv6 addresses. Out of curiosity I tried it for this IPv6 address and not unsurprisingly got nothing. I don't know if Spamhaus, or anyone else, is actually serving IPv6 address DNS blocklist information or if everyone has punted so far.)

The actual spam is your standard variety advance fee fraud spam, claiming to be from a completely unrelated email address in cox.net with replies directed to another address at 'net-c.com'. The spam message claims to be from someone with 'Egmont group, USA', which probably explains the choice of cox.net as the From: and sender address.

(The spammer probably means this Egmont group, which is plausible given the rest of the spam message, which is a typical 'we believe you have been scammed, we have some compensation to give you' thing. Since I didn't know about the Egmont group before this, I can't say that spam isn't educational.)

I have some vague thoughts on IPv6 and spam, but I've decided that they're for another entry. I have seen periodic IPv6 connections, but they appear to mostly be TLS scanners.

(My logs say that Google tried to deliver email over IPv6 back in early December, but I refused it because email from GMail to this sinkhole server is far too likely to be boring spam, usually advance fee fraud attempts. Perhaps I should declare that all spam received over IPv6 is interesting enough to capture.)