Hi,
Wireless routers like that do Network Address Translation (NAT).  You 
need to get an addressless kerberos ticket.  Since this is Fermi Linux, 
and you are using Fermi's kerberos, you get an addressless ticket by doing
   kinit -n

If you were using straight Scientific Linux, and as a result, RedHat's 
kerberos, then you would do the command
   kinit -A

And things should work for you

Troy Dawson
p.s. Since you are dealing with Fermilab, kerberos questions like this 
one probrubly would be  better answered on [log in to unmask]

Arthur Maciel wrote:
> Hello,
> For working offsite I installed FermiLinux 3.0.4, and use
> an ADSL provider over the phone line. The connection PC->
> modem->ISP->FNAL always worked fine.
> Now I added a wireless router between the PC and modem.
> The web can be accessed OK, but FNAL will nolonger honor
> my kerberos init, and sends a criptocard challenge.
> Any hints towards a cure ?
> Many thanks,
> Arthur
> PS: ADSL requires that the wireless router be setup with
>     a PPPoE type connection (in case this is part of the
>     problem).