[Exim] Specifying port on fallback host list

Hi,

Using Exim 3.16, is it possible to specify an alternate TCP port
number when giving a fallback_host list?

Or, is it simply hardcoded to 25?

Regards,

Dean A. Brooks
IgLou Internet Services, Inc.          Telephone (502) 966-3848
3315 Gilmore Industrial Blvd.          Facsimile (502) 968-0449
Louisville, Kentucky  40213            E-mail dean@???