Virtual Private Networking
146
Solution:
Confirm that the remote party has IPSec and the tunnel enabled and has
an Internet IP address. Ensure that the SnapGear appliance has rekeying enabled.
If the tunnel still goes down after a period of time, it may be due to the SnapGear
appliance and remote party not recognising the need to renegotiate the tunnel. This
situation arises when the remote party is configured to accept incoming tunnel
connections (as opposed to initiate tunnel connections) and reboots. The tunnel has
no ability to let the other party know that a tunnel renegotiation is required. This is an
inherent drawback to the IPSec protocol. Different vendors have implemented their
own proprietry method to support the ability to detect whether to renegotiate the
tunnel. SnapGear has used the draft produced by Cisco Systems (
draft-ietf-ipsec-
dpd-00.txt
) to implement dead peer detection. Unfortunately, unless the remote party
implements this draft, the only method to renegotiate the tunnel is to reduce the key
lifetimes for Phase 1 and Phase 2 for Automatic Keying (IKE). This does not occur
for Manual Keying.
•
Symptom:
Dead Peer Detection does not seem to be working
Possible Cause:
The tunnel has Dead Peer Detection disabled.
The remote party does not support Dead Peer Detection according to
draft-ietf-ipsec-
dpd-00.txt
Solution:
Enable Dead Peer Detection support for the tunnel. Unless the remote
party supports
draft-ietf-ipsec-dpd-00.txt
, Dead Peer Detection will not be used.
•
Symptom:
Tunnels using x.509 certificate authentication do not work
Possible Cause:
The date and time settings on the SnapGear appliance has not
been configured correctly.
The certificates have expired.
The Distinguished Name of the remote party has not be configured correctly on the
SnapGear appliance's tunnel.
The certificates do not authenticate correctly against the CA certificate.
The remote party's settings are incorrect.
Solution:
Confirm that the certificates are valid. Confirm also that the remote party's
tunnel settings are correct. Check the Distinguished Name entry in the the SnapGear
appliance's tunnel configuration is correct.
•
Symptom:
Remote hosts can be accessed using IP address but not by name
Possible cause:
Windows network browsing broadcasts are not being transmitted
through the tunnel.
Solution:
Set up a WINS server and use it to have the remote hosts resolve names
to IP addresses.
Содержание SnapGear
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