Gmail users dropped due to bounces

[Greg Newby]

Admin notes from your current list maintainer:

This is an FYI that perhaps Gmail-based subscribers will find in the list archives:
  https://lists.cpunks.org/pipermail/cypherpunks/

Around 50 cypherpunks subscribers were automatically removed from the list today, due to excessive bounces. These bounces were because Google throttled messages so badly that some messages were held for over 5 days and eventually bounced.

We use a standard Linux-based setup: Postfix for mail delivery and Mailman for list management. We implement the standard anti-abuse mechanisms: DMARC, SPF and DKIM.

Back in September, I reported that there were issues with list congestion (https://lists.cpunks.org/pipermail/cypherpunks/2023-September/author.html). When I looked further into what the cpunks list was experiencing, I found that it wasn't just us: Google had begun to throttle incoming messages, even when the systems sending those messages were completely compliant with all of Google's guidance on how to avoid being throttled or bounced.

Despite some changes to list settings to somewhat decrease daily list traffic, the throttling has continued for over 6 weeks.

I am manually re-subscribing the addresses that were removed, but there is no reason to think this is a long-term solution. A better solution will be to subscribe from a different service, OR to pay for a custom Google-hosted domain. I've confirmed that while @gmail.com is throttled, other Google-hosted domains are not.

Write back to the list or privately if I can help with any of this. It's unfortunate that list traffic is not getting through to some subscribers, and so I'm writing to inform everyone of what's going on and possible mitigations.
  ~ Greg Newby