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Gary Nichols wrote: |
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> Another part of good strategy would be to use SSH on a different port - |
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> most of the tools/scripts in use now do a quick scan on known services and |
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> then move on if nothing is found. If someone is directly targeting your |
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> box, this won't help much of course. :-) Sometimes it's good to maintain |
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> a low profile on management services. |
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Well, I use "port-knocking" for ssh: |
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-A INPUT -i ppp0 -m recent --set --name IN_KNOCK_SSH -m icmp -p icmp |
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--icmp-type echo-request -j DROP |
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Drop echo-request, but update (create) IN_KNOCK_SSH table. When I recive |
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a connection attempt another rule checks IN_KNOCK_SSH, and than |
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optionally open port 22. Of course you can change first rule (for |
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example icmp packet must be xxx in size). |
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-A INPUT -i ppp0 -m recent --rcheck --hitcount 4 --seconds 30 --name |
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IN_KNOCK_SSH -m state --state NEW -p tcp -m tcp --dport 2 |
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2 -j ACCEPT |
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No port is visible during normal portscans. Of course this is method is |
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not perfect. |
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-- |
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Pawe³ Goleñ |
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mailto:pawel.golen@××××××××××××××.pl |
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-- |
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gentoo-security@g.o mailing list |
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