Is it required to use GSSAPI code for the Kerberos Server Auth?

[Surendra Babu A]

Hi Team,

Could you please let me know your thoughts on the below mentioned issue.

Point #1
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I am working on SA (Server Authentication) feature of Kerberos.
- Is it required to port GSSAPI code for this feature of SA?
- If so, where should I use this mechansim in kerberos client code? That
means, between TGS_REP and AP_REQ?
- What is the exact procedure to use the GSSAPI code?

I am using MIT code and Linux Serevr (sendmail server, SMTP as the
Application server, ie I need to do server authenticatio for that SMTP
server.

POINT#2:
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I tried by sending AP_REQ to SMTP server successfuly but I could not
recevice the AP_REP successfuly. I think AP_REQ packet is not properly
understood by SMTP server since I have not been using the GSSAPI code in my
implementation. So should I port the GSSAPI code in to my code base and do
SA??

Could you please throw some light on the same?

Thank you,
-Surendra