Specifications

Open CTM (Revision D)

Command Reference

friends n x.x.x.x y.y.y.y

This command is used to setup the modem's firewall friends list, which is used to block incoming packets

from an IP address that is not specifically enabled.

Use this to define a range of IP addresses whose traffic you wish to be accepted by the modem.

This feature controls access to the following modem features:

MODBUS

PAD

ULCP

Remote SSH access (R1.3.0 only)

Remote Telnet access

Remote Web access

Port forwarding configured via firewall and the DMZ feature configured via dmz are accessible by all IP

addresses. The friends list feature does not control access to these features.

Modem access is verified in ascending order via the OR condition of all entries in the friends list.

n = 1 to 8 friends list number

x.x.x.x = 0.0.0.0 to 255.255.255.255 IP address/range to allow

y.y.y.y = 0.0.0.0 to 255.255.255.255 netmask of addresses to allow

By default, the friends list is disabled and all IP addresses are allowed to access the modem.

The current friends list can be queried by using friends without parameters. An empty friends list

indicates that this feature is disabled.

Examples:

1. Allow only incoming requests from the IP address 1.2.3.4 to access the modem

cmd friends 1 1.2.3.4 255.255.255.255

2. Allow only incoming requests from the 1.2.3.x subnet to access the modem

cmd friends 2 1.2.3.4 255.255.255.0

3. Allow only incoming requests from the 1.2.3.x subnet to access the modem. This is equivalent to

Example #2 above.

cmd friends 2 1.2.3.0 255.255.255.0

4. Disable the friends list entry and allow all IP addresses to access the modem (default)

cmd friends 1 0.0.0.0 0.0.0.0