Digi TransPort WR31 User Manual page 153

Configure network interfaces
Remote management access
The Remote access options parameter can be set to No restrictions, Disable management,
Disable return RST, Disable management an return RST.
When set to No restrictions, users on this interface can access the router's Telnet, FTP, and
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web services for the purpose of managing the router.
When set to Disable management, users on this interface are prevented from managing the
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router via Telnet, FTP, or the web interface.
For Disable return RST, whenever a router receives a TCP SYN packet for one of its own IP
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addresses with the destination port set to an unexpected value, such as a port that the router
would normally expect to receive TCP traffic on, it will reply with a TCP RST packet. This is
normal behavior. However, the nature of internet traffic is such that whenever an internet
connection is established, TCYP SYN packets are to be expected. As the router's PPP
inactivity timer is restarted each time the router transmits data (but not when it receives
data), the standard response of the router to SYN packets such as transmitting an RST
packet, will restart the inactivity timer and prevent the router from disconnecting the link
even when there is no genuine traffic. This effect can be prevented by using the appropriate
commands and options within the firewall script. However, on Digi 1000 series routers, or
where you are not using a firewall, the same result can be achieved by selecting this option,
such as when this option is selected the normal behavior of the router in responding to SYN
packets with RST packets is disabled. The option will also prevent the router from
responding to unsolicited UDP packets with the normal ICMP destination unreachable
responses.
The Disable management & return RST option prevents users from managing the router via
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the Telnet, FTP, and web interfaces and also disables the transmission of TCP RST packets as
above.
Multihome additional consecutive addresses
Defines how many additional (consecutive) addresses the Ethernet driver will own. For example,
if the IP address of the interface is 10.3.20.40, and Multihome additional consecutive
addresses is set to 3, the IP addresses 10.3.20.41, 10.3.20.42, and 10.3.20.43 also belong to the
Ethernet interface.
Enable IGMP on this interface
Enables or disables the Internet Group Management Protocol for this Ethernet interface.
Digi TransPort WR Routers User Guide
Configure Ethernet interfaces
153