I just came back from full blown forensics mode. Conclusion: everything OK, this was just caused by multiple levels of (third party) stupid.pic.twitter.com/C2kjhAs2I4
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Conclusion: the people nominally managing this server (who still use passwords) SFTPed in from the *same* ISP and they fail at CgNAT.
Apparently they're using RFC1918 space for CgNAT (which is stupid, they should use RFC6598) and it leaks into their colo servers sans NAT.
Ngl I'd be scared as hell
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