Hello, https://github.com/golang/go/issues/70232 might be interesting for you.
2025年3月15日(土) 6:07 David Landers via mailop <[email protected]>: > Earlier this week, we at Twilio SendGrid were troubleshooting timeouts > when attempting to connect to certain mail servers; specifically, we > observed an increase in TLS handshake timeouts and saturation of unused TCP > connections on our MTA servers. > > In the course of investigation, we found that some mail servers are not > compatible with the default TLS configuration in Golang standard library > version 1.23. Full details have been compiled by another party (see: > https://tldr.fail/) but the summary is that a new post-quantum secure > cryptography TLS key exchange was introduced in this version which is > incompatible with some mail servers that we are sending to, and was > directly tied to the TLS handshake timeouts we were observing. > > We compiled a list of recipient domains and associated MX servers where we > were seeing the timeouts but it's a very scattered list (e.g. small > business, .edu, and .gov domains), so thought it might be worth sharing the > summary and link to the above site here in case anyone might be impacted. > > > David Landers > Deliverability Operations Engineer > [image: %(logoAlt)s] <https://www.twilio.com/?utm_source=email_signature> > EMAIL [email protected] > _______________________________________________ > mailop mailing list > [email protected] > https://list.mailop.org/listinfo/mailop > -- Tanabe Ken-ichi HENNGE K.K. / Cloud Product Development Division [email protected] +81-3-6415-3660
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