Netgear UTM25EW-100NAS ユーザーズマニュアル
ProSecure Unified Threat Management UTM10 or UTM25 Reference Manual
C-6
System Logs and Error Messages
v1.0, September 2009
Load-Balancing Mode
When the WAN mode is configured for load balancing, both the WAN ports are active
simultaneously and the traffic is balanced between them. If one WAN link goes down, all the
traffic is diverted to the WAN link that is active.
simultaneously and the traffic is balanced between them. If one WAN link goes down, all the
traffic is diverted to the WAN link that is active.
This section describes the logs that are generated when the WAN mode is set to load balancing.
Explanation
The logs suggest that the fail-over was detected after five attempts instead of
three. However, the reason the messages appear as above is because of the
WAN state transition logic which is part of the failover algorithm. The above
logs can be interpreted as below. The primary link failure is properly detected
after the 3rd attempt. Thereafter the algorithm attempts to restart WAN and
checks once again to see if WAN1 is still down. This results in the 4th failure
detection message. If it is then it starts secondary link and once secondary link
is up, secondary link is marked as active. Meanwhile secondary link has failed
once more and that results 5th failure detection message. Note that the 5th
failure detection and the message suggesting that the secondary link is active
have the same timestamp and so they happen in the same algorithm state-
machine cycle. So, although it appears that the failover did not happen
immediately after three failures, internally, the failover process is triggered after
the 3rd failure and transition to secondary link is completed by the 5th failure.
The primary link is also restarted every three failures till it is functional again. In
the above log, primary link was restarted after the 6th failure, that is, three
failures after the failover process was triggered.
three. However, the reason the messages appear as above is because of the
WAN state transition logic which is part of the failover algorithm. The above
logs can be interpreted as below. The primary link failure is properly detected
after the 3rd attempt. Thereafter the algorithm attempts to restart WAN and
checks once again to see if WAN1 is still down. This results in the 4th failure
detection message. If it is then it starts secondary link and once secondary link
is up, secondary link is marked as active. Meanwhile secondary link has failed
once more and that results 5th failure detection message. Note that the 5th
failure detection and the message suggesting that the secondary link is active
have the same timestamp and so they happen in the same algorithm state-
machine cycle. So, although it appears that the failover did not happen
immediately after three failures, internally, the failover process is triggered after
the 3rd failure and transition to secondary link is completed by the 5th failure.
The primary link is also restarted every three failures till it is functional again. In
the above log, primary link was restarted after the 6th failure, that is, three
failures after the failover process was triggered.
Recommended Action
Check the WAN settings and WAN failure detection method configured for the
primary link.
primary link.
Table C-9. System Logs: WAN Status, Load Balancing
Message 1
Message 2
Message 3
Message 4
Message 2
Message 3
Message 4
Dec 1 12:11:27 [UTM] [wand] [LBFO] Restarting WAN1_
Dec 1 12:11:31 [UTM] [wand] [LBFO] Restarting WAN2_
Dec 1 12:11:35 [UTM] [wand] [LBFO] WAN1(UP), WAN2(UP)_
Dec 1 12:24:12 [UTM] [wand] [LBFO] WAN1(UP), WAN2(DOWN)_
Dec 1 12:29:43 [UTM] [wand] [LBFO] Restarting WAN2_
Dec 1 12:29:47 [UTM] [wand] [LBFO] WAN1(UP), WAN2(DOWN)_
Dec 1 12:11:31 [UTM] [wand] [LBFO] Restarting WAN2_
Dec 1 12:11:35 [UTM] [wand] [LBFO] WAN1(UP), WAN2(UP)_
Dec 1 12:24:12 [UTM] [wand] [LBFO] WAN1(UP), WAN2(DOWN)_
Dec 1 12:29:43 [UTM] [wand] [LBFO] Restarting WAN2_
Dec 1 12:29:47 [UTM] [wand] [LBFO] WAN1(UP), WAN2(DOWN)_
Explanation
Message 1 and Message 2 indicate that both the WANs are restarted.
Message 3: This message shows that both the WANs are up and the traffic is
balanced between the two WAN interfaces.
Message 4: This message shows that one of the WAN links is down. At this
point, all the traffic is directed through the WAN which is up
Message 3: This message shows that both the WANs are up and the traffic is
balanced between the two WAN interfaces.
Message 4: This message shows that one of the WAN links is down. At this
point, all the traffic is directed through the WAN which is up
Recommended Action
None
System Logs: WAN Status, Auto Rollover (continued)