Netopia 4000 Series, Software Manual

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Security 10-35
The new filterset screen appears as follows:
To use the policy-based routing feature, you create a filter that for wards the traffic.
■ Toggle Forward to Yes . This will display the Force Routing options.
■ Toggle Force Routing to Yes .
■ Enter the Gateway IP Address in standard dotted-quad notation to which the traffic should be for warded.
■ You can enter Source and Destination IP Address (es) and Mask (s), Protocol Type , and Source and
Destination Port ID (s) for the filter, if desired.
TOS field matching
Netopia Firmware Version 5.4 adds two additional new parameters to an IP filter: TOS and TOS Mask . Both
fields accept values in the range 0 – 255.
Cer tain types of IP packets, such as voice or multimedia packets, are sensitive to latency introduced by the
network. A delay-sensitive packet is one that has the low-latency bit set in the TOS field of the IP header. This
means that if such packets are not received rapidly, the quality of ser vice degrades. If you expect to route
significant amounts of such traffic you can configure your router to route this type of traffic to a gateway other
than your normal gateway using this feature.
The TOS field matching check is consistent with source and destination address matching.
Example: You want packets with the TOS low latency bit to go through VC 2 (via gateway 127.0.0.3) instead of
your normal gateway. You would set up the filter as follows:
Change Input Filter 1
Enabled: Yes
Forward: Yes
Call Placement/Idle Reset: No Change
Force Routing: Yes
Gateway IP Address: 163.176.8.134
Source IP Address: 0.0.0.0
Source IP Address Mask: 0.0.0.0
Dest. IP Address: 0.0.0.0
Dest. IP Address Mask: 0.0.0.0
TOS: 0
TOS Mask: 0
Protocol Type: UDP
Source Port Compare... Equal
Source Port ID: 137
Dest. Port Compare... No Compare
Dest. Port ID: 0
Return/Enter to set comparison of packet Port ID and Filter Port ID.
Enter the packet specific information for this filter.