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Comment by broodbucket | Hacker News Reader

Is this on a well-known cloud hosting provider? I assume so, unless "s3" indicates something else.

There have been attacks against known cloud hosting IP ranges for a long time. I'm constantly getting attempts on my personal server on common ports (i.e. 3128 for a proxy to spam through), that's on DigitalOcean.

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No, it's just the third server of a set, a leased dedicated bare metal CentOS server in a large data center in Phoenix AZ. No "cloud" service is involved.

This has been going on for about three weeks now. I may configure PAM to force a login delay; the logs are getting big.

Would you consider fail2ban in this case?

"Warning: Using an IP blacklist will stop trivial attacks but it relies on an additional daemon and successful logging (the partition containing /var can become full, especially if an attacker is pounding on the server). Additionally, if the attacker knows your IP address, they can send packets with a spoofed source header and get you locked out of the server. SSH keys provide an elegant solution to the problem of brute forcing without these problems."

source: https://wiki.archlinux.org/index.php/Fail2ban

> Additionally, if the attacker knows your IP address, they can send packets with a spoofed source header and get you locked out of the server.

No they can't. That is not how TCP works.

From memory, you can spoof UDP but not TCP.

https://serverfault.com/a/153619/91708

While it doesn't give any real security, changing the ssh port will at least filter out these kinds of attacks.

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