f39d9269eb rpc: warn that nodes ignore requests for old stale blocks (Sjors Provoost)
Pull request description:
Adds warning to RPC help that `getblockfrompeer` is of little use for stale blocks that are more than a month old.
This is an anti-fingerprinting measure. See `BlockRequestAllowed` in `net_processing`.
It's been in Bitcoin Core since 2014, introduced in #2910 and later improved to not rely on checkpoints.
Older and alternative clients might still serve these blocks, so not throwing an error.
Allowing whitelisted nodes to fetch these blocks anyway might be nice.
ACKs for top commit:
fjahr:
Code review ACK f39d9269eb
Tree-SHA512: db88f9f7521289640c5e629c840dda1c2c3ab70d458e9e7136c60fbaeb02acfb36dc093502d83d4c098c331e22aab81bf8f4c4961d805e3bde0f8f3cfe68d968