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16Oct/101

SSH Security: How To Block SSH Brute Force Attacks with SSHGuard

SSHGuard monitors logging activity and reacts to attacks by blocking their source IP addresses. sshguard has born for protecting SSH servers from the today's widespread brute force attacks, and evolved to an extensible log supervisor for blocking attacks to applications in real-time.

SSHGuard is given log messages in its standard input. By means of a parser, it decides whether an entry is normal activity or attack. After a number of attacks, the IP address is blocked with the firewall.

These are the available blocking backends:

  • SSHGuard with PF (OpenBSD, FreeBSD, NetBSD, DragonFly BSD)
  • SSHGuard with IP FILTER (FreeBSD, NetBSD, Solaris)
  • SSHGuard with IPFW (FreeBSD, Mac OS X)
  • SSHGuard with netfilter/iptables (Linux)
  • SSHGuard with TCP wrappers / hosts.allow (almost any UNIX system)
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12Feb/101

FreeBSD: How To boot kernel.old

If you want to boot with an old kernel, because the current one is not working properly, this is what you have to do:
During boot you get a message like:
"Booting kernel in 10 seconds or press enter..."
Just hit any key except the ENTER key and you'll get a prompt.
Type 'unload all' and then 'boot [kernel file]' where [kernel file] is the kernel you want
to boot e.g. 'kernel.old' .

Your FreeBSD machine will boot with the kernel you specified.

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