Proxy and Port Forwarding Devices

[VanDyke82nev]

I have 30 sites behind 30 Firewalls/Gateways/ASAs.

For every site, I regularly SSH to a few boxes behind the firewalls. There are a few appliances also behind the firewalls with web-page-only information on them that would make my job much easier, but I can't access them with a browser because of the firewall.

I have been doing some reading and it looks like I can use SecureCRT to connect to the routers behind the firewalls, and then map some port on my local machine to forward through my SecureCRT connection to the router which then forwards to the appliance webpage, so I can pull up the webpage on my desktop machine.

I have read that the remote machine I'm connecting to as a proxy has to have 'remote port forwarding' enabled.
Do routers typically have this 'on' or 'off'?
I can log onto the routers. How can I tell if the router has it enabled?

No 'remote port forwarding' means, no proxy, right? Just being able to SSH to a device doesn't mean I can use it as a proxy?

What devices generally work/don't work?
Linux servers?
Windows servers?
routers?
web servers?
ASAs?
Gateways?
VMs?

thank you