kerberos and setuid

[Awais Sheikh]

Hello All,
I am trying to get some clarification on this:

Can kerberos replace the use of setuid kind of applications?

Lets take a case. I need to set my application as setuid root
because I need to do a privileged operation say bind on a protected port.
Now inorder to do this, my application owner is root and is has setuid
bit enabled. As the application runs, effective user id is root, and it 
binds
on a particular port and then sets euid to real user id.

Here in order to execute this privileged task of binding on a protected
port, I had to depend on setuid environment.

How can this work in kerberised environment? Can someone help me
understand *how* if possible and if not then where is the limit?

I think for me, the missing piece is:
In order for kernel to allow the bind system call successed, it needs to
know my existing priviliges(which in kerberised environment could be a 
special
ticket to execute bind on protected port), but user-appilication never 
passed
that ticket info along with sys-call. That said, I am trying to understand
if this is possible then how does kernel know all the tickets/privileges a
user space application has been granted.

Is the answer specific to OS. Like if the ans is different for Windows vs.
Linux/Solaris/HPUX

If the Answer to this is NO.
Then how about your views "How to eliminate use of setuid?"

Thanks,
Awais

PS: Please also explicity include my email address as you reply.