setting up an ssh soxy or local ssh tunnel from within an ssh soxy
 

I did a quick search in this forum, but did not find the appropriate information. The Subject is rather confusing so allow me to expand upon it.

I'm on a computer outside a corporate network, maybe at a coffee shop or something. Let's call it homePC. I'm running Windows and I want to connect to a linux box via web browser on the corporate intranet. The problem is this linux box (let's call it corporatePC3) is three times removed from homePC. In other words, I must ssh into corporatePC1. Then ssh from corporatePC1 to corporatePC2. Finally, I can talk to corporatePC3. In essence, corporatePC1 CANNOT see corporate PC3 -- but corporatePC2 can. Remember, homePC is Windows and corporatePC1, corporatePC2, and corporatePC3 are all linux boxes.

Here's what I'm doing so far:

I'm sshing into corporate PC1 from homePC via Putty. Once I log in, I change the tunnel settings to dynamic on source port 5000 via putty configuration. Then I open up IE and change the proxy settings for SOCKS4/5 to 127.0.0.1 and port 5000. Now I can hit certain boxes via port 80 from corporatePC1.

But I want to talk to corporatePC3. So, from within the putty session (homePC to corporatePC1), I typed in ssh -D 5000 admin@corporatePC2, I typed in my password, and I'm logged on. I goto the IE web browser, but I cannot access corporatePC3. If anyone can help me, I'd REALLY appreciate it.

Thank you very much for your time and generosity.

Take care.