Digi TransPort WR11 User Manual page 369

Configuring network interfaces
disabled, because incorrect firewall rules prevent a connection from passing network traffic. If
the connection works when the firewall is turned off but fails when turned on, a good place to
start checking parameters would be in the firewall settings page, Configuration > Security >
Firewall.
Remote management access
Can be set to No restrictions, Disable management, Disable return RST, Disable
management and return RST.
When set to No restrictions, users on this interface can access the router's Telnet, FTP,
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and web services for the purpose of managing the router.
When set to Disable management, users on this interface are prevented from
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managing the router via Telnet, FTP, or the web interface.
For Disable return RST, whenever a router receives a TCP SYN packet for one of its
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own IP 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 an return RST option prevents users from managing the
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router via the Telnet, FTP, and web interfaces and also disables the transmission of TCP
RST packets as above.
3. Click Apply.
Command line
Command Instance
ppp n
ppp n
ppp n
Digi TransPort® Routers User Guide
Parameter Values
name Free text field
l1iface The layer 1
interface, such as
Async Port, PPTP, W-
WAN
l1nb Layer 1 Interface
number
Default: 0
Configure PPP and external modems
Equivalent web
parameter
Description
This PPP interface will
use
This PPP interface will
use value
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