Snapshot sync feature is still work in progress and currently is not very user-friendly yet. These are the instructions to make it work with the main net as of January 2018.
If you have Parity installed, alternative to the Downloading snapshot steps below is to get it from the directory like Parity/Ethereum/chains/ethereum/db/906a34e69aec8c0d/snapshot
1. Start downloading providing the path to the directory to save the snapshot into
aleth --download-snapshot SNAPSHOT_DIR -v 9
If it doesn't find the peer to download from, you can also provide the address of a running node with main net snapshot (can be a Parity node or an aleth node with imported snapshot)
aleth --download-snapshot SNAPSHOT_DIR -v 9 --peerset required:493d52068ec72230688da539926f47a452b762bc348d2ab1491f399b532186d71d7c512e09ffb8e9c24d292d064c00f6234ef1221bc0d86093d2de32358d33da@52.169.85.130:30303 --pin --no-discovery
The one above is an Aleth node, if it doesn't work try one of the Parity boot nodes from https://github.com/paritytech/parity/blob/master/ethcore/res/ethereum/foundation.json#L176
- Exit (Ctrl-C) when it says
Snapshot download complete!
1. Start importing the snapshot providing the path to the snapshot directory
aleth --import-snapshot SNAPSHOT_DIR -v 8
- After import is complete, it will automatically switch to regular sync process to get the blocks between snapshot and the current chain head.