fetchmail / s10/10.0.2.15

["ktb" <xyf@inebraska.com>]

I just tried using fetchmail in the 'check'  mode "fetchmail -c
mail.inebraska.com" and got the following error:

skipping poll of mail.inebraska.com, s10/10.0.2.15 down

I'm using the example ~/.fetchmailrc file.  Within that file there is an
entry:

defaults
interface "s10/10.0.2.15  #SLIRP Standard Address

I don't know what these numbers refer to.  Do I need to change these
numbers?  I can't find any numbers similar to these in my isp documentation.
What I can gather from the net SLIRP is "a TCP/IP emulator which turns a
shell account into a (C)SLIP/PPP account via modem."  I'm not sure what to
do with this.
Thanks,
kent