sudo synoipblock_list remove <IP_ADDRESS>

If your own IP has been blocked and you cannot reach the login page, use these alternative methods: IP address blocked due to too many failed attempts…

Find the IP address you want to unblock in the list.

After unblocking, the IP will immediately regain access (subject to other security rules). You may also want to add it to the to prevent re-blocking.

Or edit the block list directly:

(Optional) To prevent future blocks, go to the tab and add your local IP or subnet. How to Unblock an IP Address in DSM 6.x

Open → Security → Account tab (DSM 7) or Protection tab (DSM 6).