Technical data

93
Note 2:
The following commands are used to delete client ranges previously defined by the
system
addtelnetFilter, system addSNMPFilter, system addHTTPFilter
commands:
system deltelnetFilter <
fir
s
t ip addr
>
[
<
last ip addr
>] | LAN
system delSNMPFilter <
fir
s
t ip addr
>
[
<
last ip addr
>] | LAN
system delHTTPFilter <
fir
s
t ip addr
>
[
<
last ip addr
>] | LAN
Note 3:
To list the range of allowed clients, use the command
system list
when logged in with read and write
permission (login with password).
Restrict Remote Access
To allow management via SNMP or Telnet, while making it more difficult for non-authorized personnel to access
the router, the Telnet and SNMP ports may be redefined to a non well-known value. When Network Address
Translation (NAT) is used, this port redefinition feature also allows to continue using the standard Telnet and
SNMP ports with another device on the LAN (provided the appropriate NAT server ports commands are issued),
while simultaneously managing the router (with non-standard ports). The following commands show how this is
done.
Example:
login admin
system telnetport 4321
system snmpport 3214
Changing the SNMP Community Name
Changing the SNMP community name from its default value of “public” to another string may further enhance
SNMP security. This string then acts like a password, but this password is sent in the clear over the WAN/LAN, in
accordance with the SNMP specification.
The SNMP community name is changed using the following commands:
login admin
system community <
snmp community name
> -- (eg:
system community fred)
save
reboot
Disable WAN Management
It may be desirable to allow management of the router on the local LAN, but not over the WAN Network. If the
router has been configured to use NAT, then by defining two servers, that DO NOT exist, on the LAN side to
handle WAN SNMP and Telnet requests, WAN management of the router cannot occur. The following commands
show how this could be done.
Example:
login admin
system addServer 192.168.254.128 udp snmp - (no computer at 192.168.254.128)
system addServer 192.168.254.128 tcp telnet
save
reboot