Subject: Re: FC6 VPN
Date: Tue, 19 Dec:23:23 +0000
Jim Douglas wrote:
> VPN w/ SSH is overkill I think, all I need is to securely access a remote
> box...from Windows Client -> Linux Server.
Very often that will involve PuTTY. PuTTY also makes tunnelling very
easy, and is a *very* good terminal emulator.
> I think I found the answer,
>
> I have SSH up and running, anyone have any good links to securing my SSH
> configuration?
1. Stick to SSH 2 (in /etc/ssh/sshd_config, use the Protocol keyword)
2. Set up private keys and disable password-based logins
3. Changing the port that SSH listens on will not deter a determined
attacker, but may help you work out that you've got a determined
attacker.
4. Make sure you run yum update regularly.
5. Use AllowUsers or AllowGroups to limit which users can log on
remotely. Don't allow direct root logins -- get users to login as
themselves and su - (this means attackers have to work out which
usernames are valid).
6. If you must use passwords, make sure they're not dictionary words and
include at least one (better, several) numbers or symbols.
7. Distribute the server public keys via trusted networks -- don't trust
the client's ability to "learn" the server's key when it first
connects, since you don't know that the remote computer really *is*
your server.
But really, there's not much securing needed with SSH. It's only really
vulnerable to a security bug at either end, a dictionary attack, a
man-in-the-middle attack during the first connection, or some new,
unknown mathematics.
Hope this helps,
James.
--
E-mail: james@ | For every complex problem, there is a solution that is
aprilcottage.co.uk | simple, neat, and wrong.
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fedora-list mailing list
One final question...
I can connect to port 22 inside the firewall and I don't want to create any holes. Can you see any problems with adding this to iptables?
iptables -I RH-Firewall-1-INPUT 3 -p tcp -m tcp --dport 22 --tcp-flags SYN,RST,ACK SYN -j ACCEPT
