IPCop has a built in (although sometimes broken) download/apply UI for patches / security updates. However, it is broken sometimes, and there are times where it’s easier do it over SSH (slow, or unreliable connectivity, for example). Having Googled a bit, there wasn’t an immediate or obvious solution, so I dug around in the CGI scripts to see how it’s done.
This solution (as user Ederson notes in the comments) is applicable to later versions of IPCop 1.x. This has not been tested on the current IPCop 2.x.
Firstly, download the patch using wget, for example:
Then, move that patch as follows:
mv ipcop-1.4.21-update.i386.tgz.gpg /var/patches/patch.tgz.gpg
That destination file shouldn’t already exist, so if it does you may need to investigate why the previous patch wasn’t applied correctly.
Finally, apply the patch:
You’ll be prompted when the patch is applied. Reboot if the patch requires so.