D-Link 2560G Network Router User Manual


 
1. Could not find acceptable proposal / no proposal chosen
This is the most common IPsec related error message. It means that depending on which side
initiates tunnel setup, the negotiations in either the IKE or the IPSec phase of setup failed since they
were unable to find a matching proposal that both sides could agree on.
Troubleshooting this error message can be involved since the reasons for this message can be
multiple depending on where in the negotiation it occurred.
If the negotiation fails during phase-1 – IKE
The IKE proposal list does not match. Double check that the IKE proposal list matches that of
the remote side. A good idea is to use the ikesnoop verbose command in the console and get the
tunnel to initiate the tunnel from the remote side. You will be able to then see what proposals the
remote side is sending and then compare the results with your own IKE proposal list. At least
ONE proposal has to match in order for it to pass phase-1. Don't forget that the lifetimes are also
important as will be mentioned in Problem symptom-1. Note: In newer versions it is not possible
to set the lifetime in KB for the IKE Phase, only seconds.
If the negotiation fails during phase-2 – IPsec
The IPsec proposal list does not match. Double check that the IPsec proposal list matches that of
the remote side. You can use the same method described above of using ikesnoop from when the
remote side initiates the tunnel and compare it against your own proposal list. What is "extra" in
the IPsec phase is that the networks are negotiated here, so even if the IPsec proposal list seem
to match the problem may be with mismatching networks. The Local Network(s) on your side
needs to be the Remote Network on the other side and vice versa. Remember that multiple
networks will generate multiple IPsec SA's, one SA per network (or host if you use that option).
The defined network size is also important in that it must have exactly the same size on both
sides, as will be mentioned again later in the symptom section.
There are also some settings on the IPsec tunnel's IKE tab that can be involved in a no-proposal
chosen issue. Such as Main or Aggressive mode, DH Group (for the IKE phase) and PFS (for
IPsec phase).
2. Incorrect pre-shared key
A problem with the pre-shared key on either side has caused the tunnel negotiation to fail. This is
perhaps the easiest of all the error messages to troubleshoot since it can be only one thing, and that
is incorrect pre-shared key. Double-check that the pre-shared key is of the same type (Passphrase or
Hex-key) and correctly added on both sides of the tunnel.
Another reason for why NetDefendOS detects that the pre-shared key is incorrect could be because
the wrong tunnel is triggering during tunnel negotiations. IPsec tunnels are processed from the top
to the bottom of the NetDefendOS tunnel list and are initially matched against the remote gateway.
An example is if there is a roaming tunnel that uses all-nets as its remote gateway. This tunnel will
trigger before your defined tunnel if it is above it in the tunnel list.
For example, consider the following IPsec tunnel definitions:
Name Local Network Remote Network Remote Gateway
VPN-1 lannet office1net office1gw
VPN-2 lannet office2net office2gw
L2TP ip_wan all-nets all-nets
VPN-3 lannet office3net office3gw
Since the tunnel L2TP in the above table is above the tunnel VPN-3, it will trigger a match before
VPN-3 because of the all-nets remote gateway (all-nets will match any network). Since these two
9.7.5. Specific Error Messages Chapter 9. VPN
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