For 1., i think ipsec check the integrity of each packet, who is it coming from, who is it going to etc. And it's doing a kind of checksum of each packet, on the data if contains.
Also you have two modes in ipsec.
partial answer anyway...You can read freeswan documentation ;p there is more explanation about it
There's a list of third party clients for windows but it seems that none of them are free except the one builded in win2k
From: Patrick Hsieh [mailto:email@example.com]
Sent: 19 November 2002 01:23
To: Jamin W. Collins
Subject: Re: pptp vpn
I have two question about pptp vpn:
1. Is pptp+mppe any insecure? Why? Since the pptpd server can force the
connection to use mppe encryption with the client. How come pptp+mppe is
insecure? Is it because the encryption algorithm or lack of the public key
2. I can easily install freeswan on Linux, but where can I find the Windows
client that can talk with freeswan server?
GnuPG Pubilc Key at http://www.ezplay.tv/~pahud/pahudatezplay.pubkey
MD5 checksum: b948362c94655b74b33e859d58b8de91
1024D/F3662014 9ADF 6E3F 68DE 8DF8 4A67 0B54 6608 BAA8 F366 2014
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