D-Link DFL-260 Product Manual - Page 439

Management Interface Failure with VPN, 9.7.5. Specific Error Messages, console command

Page 439 highlights

9.7.4. Management Interface Failure with VPN Chapter 9. VPN Another example of what to avoid with many tunnels is: gw-world:/> ipsectunnels -num=all In these circumstances, using the option with a small number, for example -num=10, is recommended. The ikesnoop console command A common problem with setting up IPsec is a list of proposed algorithms that is unacceptable to the device at the other end of the tunnel. The ikesnoop command is a useful tool for diagnosing incompatible algorithm proposal lists by showing the details of negotiations during tunnel setup. The basic form of this command is: gw-world:/> ikesnoop -on -verbose Once issued, an ICMP ping can then be sent to the NetDefend Firewall from the remote end of the tunnel. This will cause ikesnoop to output details of the tunnel setup negotiation to the console and any algorithm proposal list incompatibilities can be seen. If there are multiple tunnels in a setup or multiple clients on a single tunnel then the output from verbose option can be overwhelming. It is therefore better to specify that the output comes from a single tunnel by specifying the IP address of the tunnel's endpoint (this is either the IP of the remote endpoint or a client's IP address). The command takes the form: gw-world:/> ikesnoop -on -verbose Ikesnoop can be turned off with the command: gw-world:/> ikesnoop -off For a more detailed discussion of this topic, see Section 9.4.5, "Troubleshooting with ikesnoop". 9.7.4. Management Interface Failure with VPN If any VPN tunnel is set up and then the management interface no longer operates then it is likely to be a problem with the management traffic being routed back through the VPN tunnel instead of the correct interface. This happens when a route is established in the main routing table which routes any traffic for all-nets through the VPN tunnel. If the management interface is not reached by the VPN tunnel then the administrator needs to create a specific route that routes management interface traffic leaving the NetDefend Firewall back to the management sub-network. When any VPN tunnel is defined, an all-nets route is automatically defined in the routing table so the administrator should always set up a specific route for the management interface to be correctly routed. 9.7.5. Specific Error Messages This section will deal with specific error messages that can appear with VPN and what they indicate. The messages discussed are: 1. Could not find acceptable proposal / no proposal chosen. 2. Incorrect pre-shared key. 3. Ike_invalid_payload, Ike_invalid_cookie. 4. Payload_Malformed. 5. No public key found. 439

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Another example of what to avoid with many tunnels is:
gw-world:/>
ipsectunnels -num=all
In these circumstances, using the option with a small number, for example
-num=10
,
is recommended.
The
ikesnoop
console command
A common problem with setting up IPsec is a list of proposed algorithms that is unacceptable to the
device at the other end of the tunnel. The
ikesnoop
command is a useful tool for diagnosing
incompatible algorithm proposal lists by showing the details of negotiations during tunnel setup.
The basic form of this command is:
gw-world:/>
ikesnoop -on -verbose
Once issued, an ICMP
ping
can then be sent to the NetDefend Firewall from the remote end of the
tunnel. This will cause
ikesnoop
to output details of the tunnel setup negotiation to the console and
any algorithm proposal list incompatibilities can be seen.
If there are multiple tunnels in a setup or multiple clients on a single tunnel then the output from
verbose
option can be overwhelming. It is therefore better to specify that the output comes from a
single tunnel by specifying the IP address of the tunnel's endpoint (this is either the IP of the remote
endpoint or a client's IP address). The command takes the form:
gw-world:/>
ikesnoop -on <ip-address> -verbose
Ikesnoop can be turned off with the command:
gw-world:/>
ikesnoop -off
For a more detailed discussion of this topic, see
Section 9.4.5, “Troubleshooting with ikesnoop”
.
9.7.4. Management Interface Failure with VPN
If any VPN tunnel is set up and then the management interface no longer operates then it is likely to
be a problem with the management traffic being routed back through the VPN tunnel instead of the
correct interface.
This happens when a route is established in the main routing table which routes any traffic for
all-nets
through the VPN tunnel. If the management interface is not reached by the VPN tunnel then
the administrator needs to create a specific route that routes management interface traffic leaving the
NetDefend Firewall back to the management sub-network.
When any VPN tunnel is defined, an
all-nets
route is automatically defined in the routing table so
the administrator should always set up a specific route for the management interface to be correctly
routed.
9.7.5. Specific Error Messages
This section will deal with specific error messages that can appear with VPN and what they indicate.
The messages discussed are:
1.
Could not find acceptable proposal / no proposal chosen.
2.
Incorrect pre-shared key.
3.
Ike_invalid_payload, Ike_invalid_cookie.
4.
Payload_Malformed.
5.
No public key found.
9.7.4. Management Interface Failure
with VPN
Chapter 9. VPN
439