Technical Tip: Option to select source interface and address for Telnet and SSH

[Rosalyn]

Description
From FortiOS 7.0, new commands' execute telnet-options' and 'execute ssh-options' allow administrators to set the source interface and address for their connection.
This article explains these commands

# execute telnet-options {interface <outgoing interface> | reset | source <source interface IP> | view-settings}
# execute ssh-options {interface <outgoing interface> | reset | source <source interface IP> | view-settings}

Solution
To edit the Telnet options:

# execute telnet-options interface port1
# execute telnet-options source 1.1.1.1

To confirm that the Telnet packets are using the configured port and address:

# diagnose sniffer packet any "port 23" 4
4.070426 port1 out 1.1.1.1.13938 -> 15.15.15.2.23: syn 400156130
4.070706 port1 in 15.15.15.2.23 -> 1.1.1.1.13938: syn 2889776642 ack 400156131

To edit the SSH options:

# execute ssh-options interface port1
# execute ssh-options source 1.1.1.1

To confirm that the SSH packets are using the configured port and address:

# diagnose sniffer packet any "port 22" 4
6.898985 port1 out 1.1.1.1.20625 -> 15.15.15.2.22: syn 1704095779
6.899286 port1 in 15.15.15.2.22 -> 1.1.1.1.20625: syn 753358246 ack 1704095780