-----Original Message----- From: centos-bounces at centos.org [mailto:centos-bounces at centos.org] On Behalf Of Eugene Vilensky Sent: Thursday, August 20, 2009 10:15 PM To: CentOS mailing list Subject: [CentOS] protecting multiuser systems from bruteforce ssh attacks Hello, What is the best way to protect multiuser systems from brute force attacks? I am setting up a relatively loose DenyHosts policy, but I like the idea of locking an account for a time if too many attempts are made, but to balance this with keeping the user from making a helpdesk call. What are some policies/techniques that have worked for this list with minimal hassle? Hi Eugene, Depends on the number of users (as you mentioned "mutisuser" ) And how strong you want your system to be protected. If its not a couple of thousands, i would suggest: Disabling password-login alltogether, and use keys only. On the other hand, you can also demand that all connection must be made by using a vpn-connection (openvpn/ipsec). After that you can be assured that any attempt is from a local user. Both are a much stronger protection than allow/deny or firewall-mechanisms Hans ______________________________________________________________________ Dit bericht kan informatie bevatten die niet voor u is bestemd. Indien u niet de geadresseerde bent of dit bericht abusievelijk aan u is toegezonden, wordt u verzocht dat aan de afzender te melden en het bericht te verwijderen. De Staat aanvaardt geen aansprakelijkheid voor schade, van welke aard ook, die verband houdt met risico's verbonden aan het elektronisch verzenden van berichten. This message may contain information that is not intended for you. If you are not the addressee or if this message was sent to you by mistake, you are requested to inform the sender and delete the message. The State accepts no liability for damage of any kind resulting from the risks inherent in the electronic transmission of messages.