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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [FW-1] ike vpn question
I think it works like this: Packet leaves net A which is in the encryption domain for firewall A. Key exchange is attempted from firewall A to firewall B (the other end of the VPN). Firewall B sees subnet A in the offered key, but has no entry for A in its version of the encryption domain, so refuses the exchange. This could be interpreted as "no proposal chosen" in my opinion, and in fact I have seen exactly this with my own VPN's when I forget to add the net range to the other end... Thanks, Jeff LaCoursiere Infrastructure Specialist T-Motion -----Original Message----- From: Russell Washington [mailto:[email protected]] Sent: Tuesday, March 19, 2002 7:04 PM To: [email protected] Subject: Re: [FW-1] ike vpn question Ok, dug this up in RFC2408: Proposal: A proposal is a list, in decreasing order of preference, of the protection suites that a system considers acceptable to protect traffic under a given situation. This translates to me as "encryption settings" on an IPSec-compliant platform. Shouldn't involve the source/target if "no proposal chosen" is the specific error being reported. -----Original Message----- From: Russell Washington [mailto:[email protected]] Sent: Tuesday, March 19, 2002 10:23 AM To: [email protected] Subject: Re: [FW-1] ike vpn question Could well be, but my recollection is that target/destination stuff in Phase 2 negotiation is a source proxy ID/dest proxy ID issue, not a proposal issue. On the devices where I've seen 'no proposal chosen' and subnet issues, they've turned up with different errors for each condition (or in the case of a Checkpoint to PIX with a subnet issue, the PIX just didn't answer at all). Doesn't mean he shouldn't check the encryption domains tho. Really curious over here to hear what he finds. -----Original Message----- From: Shah, Nishith [mailto:[email protected]] Sent: Tuesday, March 19, 2002 9:09 AM To: [email protected] Subject: Re: [FW-1] ike vpn question Most likely your encryption domains (subnets defined on firewall) are not identical on both sides. It has to exactly match on both sides. -----Original Message----- From: Russell Washington [mailto:[email protected]] Sent: Tuesday, March 19, 2002 11:23 AM To: [email protected] Subject: Re: [FW-1] ike vpn question "No proposal chosen" means that the encryption settings on each end are not in sync. Yes, I know you said they're identical, but that's what the error means and I believe it's defined in an RFC somewhere. As cryptic as it sounds, it's being as precise as it will get without saying something verbose like "it says use DES on this side and 3DES on the other side and so we don't agree." Here's the rundown of settings (cross-platform) that I know will tangle this up: - preshared key vs RSA key vs certificates - DES vs 3DES vs (who knows what else) - ESP vs AH vs ESP+AH at the same time - Perfect forward secrecy (PFS) on vs off - Diffie-Hellman group for PFS (Group 1? Group 2? Group 3?) What I've most often seen overlooked is the PFS/DH stuff. One side has it on, the other has it off, or the two sides are using different DH groups. Good luck. I haven't seen one of these yet that didn't boil down to a mismatched setting between the two sides, and that includes the Checkpoint, NetScreen, and Cisco platforms. -----Original Message----- From: Christopher Ferraro [mailto:[email protected]] Sent: Tuesday, March 19, 2002 6:51 AM To: [email protected] Subject: [FW-1] ike vpn question Gentlemen: I have a question for you regarding a VPN a client of mine is attempting to set up. Both VPNs have identical hardware (nokia 650's), identical software (checkpoint 4.1, sp4). All encryption settings are identical. However, when the VPN ruleset is built, an error is seen in the log on one end of the VPN that says "IKE log: received notification from peer, no proposal chosen." what is the root of errors of this nature ? I will provide more relevant information as necessary. CF Christopher A. Ferraro Senior Systems Engineer Hubbard Onemobile:www.hubbardone.com ================================================= To set vacation, Out Of Office, or away messages, send an email to [email protected] in the BODY of the email add: set fw-1-mailinglist nomail ================================================= To unsubscribe from this mailing list, please see the instructions at http://www.checkpoint.com/services/mailing.html ================================================= If you have any questions on how to change your subscription options, email [email protected] =================================================
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