Port knocking is a method of externally opening ports, which, by default, the firewall keeps closed, by generating a connection attempt on a set of pre-specified closed ports.
Termius provides a port knocking client that supports both UDP and TCP protocols and inter-packet delays.
To send a knock sequence in Termius, you'll need to:
Create a port knocking type of snippet (see below).
Run it from the Snippets screen.
⚠ You must have a port knock daemon running on your server to make use of this feature.
Navigate to the Snippets screen.
Tap + and then Port Knocking Snippet.
(Optional) In the Name field, specify a name of the snippet.
(Optional) In the Default Destination field, specify a host that will be receiving the knock sequence.
In the Knock Sequence section, create a knock sequence. Each item in the sequence is either a TCP or UPD packet sent to a required port, or a delay (pause).
ℹ Tap and hold an item in the sequence to re-arrange it.