Subject: [bitcoin-dev] Bitcoin Core to disable Bloom-based Filtering by default

From: Matt Corallo <[email-masked]>
Date: Sat, 20 Jul 2019 17:46:52 +0000

Just a quick heads-up for those watching the list who may be using it -
in the next Bitcoin Core release bloom filter serving will be turned off
by default. This has been a long time coming, it's been an option for
many releases and has been a well-known DoS vector for some time.
As other DoS vectors have slowly been closed, this has become
increasingly an obvious low-hanging fruit. Those who are using it should
already have long been filtering for NODE_BLOOM-signaling nodes, and I
don't anticipate those being gone any time particularly soon.

See-also PR at https://github.com/bitcoin/bitcoin/pull/16152

The release notes will liekly read:

P2P Changes
-----------
- The default value for the -peerbloomfilters configuration option (and,
thus, NODE_BLOOM support) has been changed to false.
  This resolves well-known DoS vectors in Bitcoin Core, especially for
nodes with spinning disks. It is not anticipated that
  this will result in a significant lack of availability of
NODE_BLOOM-enabled nodes in the coming years, however, clients
  which rely on the availability of NODE_BLOOM-supporting nodes on the
P2P network should consider the process of migrating
  to a more modern (and less trustful and privacy-violating) alternative
over the coming years.

Matt