[CentOS] CentOS VPN server for iPhone

Scott Silva ssilva at sgvwater.com
Thu Mar 26 21:11:37 UTC 2009


on 3-26-2009 1:02 PM Florin Andrei spake the following:
> Les Mikesell wrote:
>> If you have a decent password (on all accounts) I wouldn't worry about 
>> about it too much.  Move it to an odd port or even require a client 
>> certificate if your client software supports it.
> 
> The non-standard port is a good trick, but even assuming the iPhone does 
> support it (which is far from certain, the interface is very simple and 
> terse), I'm still a bit uncomfortable. All it takes is a stupid buffer 
> overflow, and a script kiddie with patience and a portscanner - even if 
> you send packets to DROP, it's still scannable, it just takes much 
> longer. Port knocking is probably not doable (or not easily) from the 
> iPhone.
> 
> Maybe I don't trust the IMAP server enough to expose it. Maybe I should.
> 
>> The usual problem with IPSec is trying to make it work through a NAT 
>> router.   Does your server have a public address of its own?   SSL and 
>> OpenVPN can work through port-forwarding routers.
> 
> I'm aware of the NAT issues. I've a decent amount of experience with 
> IPSec in the enterprise actually, just not with Linux as a concentrator. 
> The usual trick is to enable some sort of UDP tunneling, and then a good 
> part of those issues is alleviated. The question is whether the Linux 
> IPSec server supports UDP encapsulation (and whether the iPhone client 
> does too).
> 
> The machine has a public interface exposed directly to the Internet, so 
> that simplifies things a bit.
> 
I have several IMAP servers exposed. I just run fail2ban and it drops the
script kiddies and the brute force attacks after a couple of tries.
Unless the attacker already knows the username and password, that should stop
them cold.

-- 
MailScanner is like deodorant...
You hope everybody uses it, and
you notice quickly if they don't!!!!

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