brute force ssh attacks

[Lonni J Friedman]

For the past few days some bot net has decided to attempt to attack
sshd on one of my systems with some kind of brute force attach.  Its
coming from literally a broad swadth of the internet with connection
attempts like this in the past 24 hours:

    1.9.46.177: 6 times
    1.22.91.179: 5 times
    1.23.144.150: 3 times
    1.34.164.204 (1-34-164-204.HINET-IP.hinet.net): 2 times
    1.34.177.7 (1-34-177-7.HINET-IP.hinet.net): 1 time
    1.119.131.102: 5 times
    1.179.146.156: 2 times
    1.179.185.50: 2 times
    1.180.16.156: 3 times
    1.180.17.229: 2 times
    1.180.17.239: 3 times
    1.180.17.245: 2 times
    1.180.17.253: 3 times
    1.192.126.125: 1 time
    1.194.238.224: 3 times
    1.202.165.40 (40.165.202.1.static.bjtelecom.net): 3 times
    1.236.151.31: 1 time
    2.6.219.46 (apoitiers-654-1-28-46.w2-6.abo.wanadoo.fr): 1 time
    2.31.102.13: 1 time
    2.238.129.59 (2-238-129-59.ip244.fastwebnet.it): 1 time
    3.8.16.138 (ec2-3-8-16-138.eu-west-2.compute.amazonaws.com): 5 times
    3.8.84.231 (ec2-3-8-84-231.eu-west-2.compute.amazonaws.com): 2 times
    3.17.39.75 (ec2-3-17-39-75.us-east-2.compute.amazonaws.com): 4 times
    3.104.123.118
(ec2-3-104-123-118.ap-southeast-2.compute.amazonaws.com): 5 times
    3.122.149.254
(ec2-3-122-149-254.eu-central-1.compute.amazonaws.com): 4 times
    5.2.152.160 (static-5-2-152-160.rdsnet.ro): 3 times
    5.9.7.117 (static.117.7.9.5.clients.your-server.de): 3 times


Except, that its a few thousand attempts every day.  I'm already not
permitting password based auth for sshd, so the entire exercise is
futile, but its definitely consuming resources on my side.  I'm aware
of tools like fail2ban, but I'm not sure that's going to be much value
when the attacks are a few attempts from a very large number of unique
sources.

Are there any other good solutions for preventing this sort of thing
beyond blocking sshd from everywhere except white listed IP addresses?

thanks