problem in making krb5kdc listen on tcp port

[Vipin Rathor]

hi all,
    i've installed & configured *MIT-krb1.5* on RHEL4(64 bit). and initially
it was running smooth on udp port.
Now i wanted to run krb5kdc on tcp port.
So i killed the krb5kdc daemon. then added
*[kdcdefaults]
        kdc_tcp_ports = 88*
in */var/kerberos/krb5kdc/kdc.conf *file.
I also checked that there are entries in */etc/services *file as

kerberos        88/tcp          kerberos5 krb5  # Kerberos v5
kerberos        88/udp          kerberos5 krb5  # Kerberos v5

After this, when i restarted the *krb5kdc* and in the log file, it wrote,

Jul 18 17:08:12  krb5kdc[10347](info): listening on fd 7: udp <ip>.750
Jul 18 17:08:12  krb5kdc[10347](info): listening on fd 8: udp <ip>.88

So my problem is:
1.) Why am i not able to get the krb5kdc listen on tcp port?
2.) Is there any other setting required?

A quick response will be highly appreciated...

Thanx & regards,
-Vipin Rathor