Bind a fake service to a tcp port

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http://serverfault.com – A friend of mine gives me a (user) ssh access on an ec2-instance (ubuntu) that he's got. So, for reason that now I don't know, in the future I will have need of an open tcp port over the firewall to make listening some sort of service (like http or other). I don't want to stress him every time that I need a tcp open port in the firewall but, meanwhile, I don't want to leave open (and vulnerably unbinded) a port on his firewall. The question is: is there a way to fake bind (in the way that this fake service occupy) this tcp port? Or is there another "pattern" to accomply this issue? (HowTos)