Category Archives: Security

Limit/prevent SSH brute force attempts

If you (have to) run a public available SSH server, you may have noticed already that there are a lot of brute force attacks trying to guess a user and password (have a look into /var/log/secure ). If you did it the correct way, you only allow public keys to authenticate of course. But maybe you can’t, because the client … Continue reading

Posted in CentOS, Firewalls, Linux, Security | Tagged , , , , | 1 Comment

Virus Alarm!

Today i have a nice one… OK, maybe not THAT nice, as you can expect from the title. This morning i recognized that folders on network shares looked different than they should. After connecting to the file server it was almost clear instantly. A virus… For normal users (with default file explorer settings) it looked almost as usual. But, after … Continue reading

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Quick tip: Limiting RPC dynamic port range

One annoying thing with RPC is, that it is configured to use over 16’000 ports by default (in 2008 Server). That’s absolutely not needed in most cases. I normally limit the range to 1000 ports which is more than enough, and makes firewall administrators a bit more happy… a bit… To change the port range to f.ex. 43000-43999 you have … Continue reading

Posted in Firewalls, Security, Windows Server | Tagged , , , , , | Leave a comment