Policy Configuration : Configuring IP Helper
Configuring IP Helper
The IP Helper allows the SonicWALL to forward DHCP requests originating from the interfaces on a SonicWALL to a centralized DHCP server on the behalf of the requesting client. IP Helper is used extensively in routed VLAN environments where a DHCP server is not available for each interface, or where the layer three routing mechanism is not capable of acting as a DHCP server itself. The IP Helper also allows NetBIOS broadcasts to be forwarded with DHCP client requests.
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NOTE: IP Helper is only supported in SonicOS Enhanced.
To enable IP Helper and add an IP Helper policy, complete the following steps:
1
Expand the Network tree and click IP Helper. The IP Helper page displays.
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Select Enable IP Helper.

For appliances running SonicOS Enhanced versions lower than 5.5, you can also configure DHCP and NetBIOS support:
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To enable DHCP support, select Enable DHCP Support.
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To enable NetBIOS support, select Enable NetBIOS Support.
Configuring Relay Protocols
Appliances running SonicOS Enhanced versions 5.5 and higher support Enhanced IP Helper that offers configurable Relay Protocols.
Appliances running SonicOS Enhanced 6.1 and higher have default Relay Protocols available.
The following built-in applications are included:
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DHCP—UDP port number 67/68
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Net-Bios NS—UDP port number 137
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Net-Bios Datagram—UDP port number 138
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DNS—UDP port number 53
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Time Service—UDP port number 37
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Wake on LAN (WOL)
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mDNS—UDP port number 5353; multicast address 224.0.0.251
To enable any of these protocols, select Enable and click Update.
To configure additional protocols, complete the following steps:
1
Click Add Relay Protocol. The Add IP Helper Application window displays.
 
2
Configure the following options:
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Name—The name of the protocols. Note that these are case sensitive and must be unique.
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Port 1/2—The unique UDP port number.
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Translate IP—Translation of the source IP while forwarding a packet.
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Timeout—IP Helper cache timeout in seconds at an increment of 10.
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Raw Mode—Unidirectional forwarding that does not create an IP Helper cache. This is suitable for most of the user-defined protocols that are used for discovery, for example WOL/mDNS.
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Click Update.
Configuring IP Helper Policies
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To add an IP Helper Policy, click Add IP Helper Policy. The Add IP Helper dialog box displays.
 
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The policy is enabled by default. To configure the policy without enabling it, clear Enabled.
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Click the Protocol drop-down menu and select one of the following:
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DHCP
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NetBIOS
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DNS
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TIME
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WOL
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mDNS
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ss
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Select a source Interface or Zone from the From menu.
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Select a destination IP address or subnet from the To menu.
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Enter an optional comment in the Comment field.
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Click OK to add the policy to the IP Helper Policies table.
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Repeat this procedure for each policy to add. To delete a policy, click the trash can icon next to the policy.
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When you are finished, click Update. The settings are changed for the selected SonicWALL appliance. To clear all screen settings and start over, click Reset.