Firewall Wizards mailing list archives
Re: NAT
From: Tina Bird <tbird () iegroup com>
Date: Sat, 13 Jun 1998 00:33:29 -0500
This isn't true! I'm aware of a large number of VPN installations, both IPSec and proprietary, which work quite happily with NAT. Even PPTP is interoperable now with address translation, at least once you've got your routes set up correctly. F'r instance: Sidewinder firewalls perform NAT "by default" - that is, you can't have a live Sidewinder that >doesn't< have address translation thanks to the two-or-more NICs, and the lack of IP forwarding. Sidewinder supports IPSec in both transport and tunnel modes, allowing the VPN to terminate on either the external side of the firewall (in which case the unencrypted, destination side of the IPSec association is the "final" destination, as far as the VPN is concerned) or on the internal side of the firewall (in which case the firewall hands off the traffic to the destination machine on the interior network). In either case, the firewall is the decryption server, and it's only ever the external firewall IP address which is visible to the public network. I've worked with 3 or 4 other VPN products (Alta Vista, PPTP, VTCP/Secure and Signal 9) with similar success in a NAT environment. Tina Bird Burden, James wrote:
John, Besides RFC1918 you can read RFC1631 - The IP Network Address Translator (NAT). K. Egevang & P. Francis. May 1994. (Format: TXT=22714 bytes) (Status: INFORMATIONAL). I am not aware of a pro/cons white paper yet. However, VPN (example: IPSEC) technologies are costly and kludgey working with NAT. If IP headers are encrypted then a tunnel would have to begin and end any where NAT is used. Jim James Burden Phone - 916.351.2243 Security Engineer Page - 916.814.2563 California ISO Fax - 916.351.2181 http://www.caiso.com Email - jburden () caiso com 41DF 0E4C 26E0 2FD3 8C81 A260 5C40 280E B4AE 7420 ____________________________________________ To Teach is to Learn - Aaron Nimzovich ____________________________________________-----Original Message----- From: Appel, John [SMTP:AppelJ () 1st-annapolis com] Sent: Wednesday, June 10, 1998 12:05 PM To: 'firewall-wizards () nfr net' Subject: NAT Is there a FAQ or similar document covering the pros/cons/caveats of NAT? TIA, John
Current thread:
- NAT Appel, John (Jun 11)
- <Possible follow-ups>
- RE: NAT Burden, James (Jun 12)
- Re: NAT Tina Bird (Jun 13)
- Re: NAT Ryan Russell (Jun 15)
- Re: NAT Rick Smith (Jun 17)
- RE: NAT Burden, James (Jun 16)
- Re: NAT Tina Bird (Jun 17)
- Re: NAT Ryan Russell (Jun 17)
- Re: NAT Rick Smith (Jun 17)
- Re: NAT Ryan Russell (Jun 17)
- Re: NAT Ryan Russell (Jun 17)