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                                                                      Exhibit F

                             JOINT FILING AGREEMENT

                  In accordance with Rule 13d-1(k)(1)(iii) of the Securities
Exchange Act of 1934, as amended, the undersigned agree to the joint filing on
behalf of each of them of a Statement on Schedule 13D (including any and all
amendments thereto) with respect to the Common Stock, par value $0.02 per share,
of IFX Corporation, and further agree that this Agreement shall be included as
an Exhibit to such joint filing.

                  The undersigned further agree that each party hereto is
responsible for timely filing of such statement on Schedule 13D and any
amendments thereto, and for the completeness and accuracy of the information
concerning such party contained therein; provided that no party is responsible
for the completeness or accuracy of the information concerning the other
parties, unless such party knows or has reason to believe that such information
is inaccurate.

                  This Agreement may be executed in one or more counterparts,
each of which shall be deemed to be an original instrument, but all of such
counterparts together shall constitute but one agreement.

                  In evidence thereof the undersigned, being duly authorized,
hereby execute this Agreement this 26th day of June, 2000.


                                   UBS CAPITAL AMERICAS III, L.P.
                                       By: UBS Capital Americas (LA-Advisor) LLC


                                   By:  /s/ Charles W. Moore
                                       --------------------------------
                                            Name:   Charles W. Moore
                                            Title:  Principal


                                   By:  /s/ Marc Unger
                                        --------------------------------
                                            Name:   Marc Unger
                                            Title:  Chief Financial Officer



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                                   UBS CAPITAL JERSEY CORPORATION II,
                                     LTD.


                                   By: /s/ Derek Smith
                                       -----------------------------------------
                                            Name:  Derek Smith
                                            Title: Director


                                   By: /s/ Andrew Evans
                                       -----------------------------------------
                                            Name:  Andrew Evans
                                            Title: Director


                                   UBS CAPITAL AMERICAS (LA-ADVISORS)
                                   LLC


                                   By: /s/ Charles W. Moore
                                       -----------------------------------------
                                            Name:  Charles W. Moore
                                            Title: Principal



                                   By: /s/ Marc Unger
                                       -----------------------------------------
                                            Name:  Marc Unger
                                            Title: Chief Financial Officer


                                   UBS AG


                                   By: /s/ Robert Mills
                                       -----------------------------------------
                                            Name:  Robert Mills
                                            Title: Managing Director



                                   By: /s/ Richard Capone
                                       -----------------------------------------
                                            Name:  Richard Capone
                                            Title: General Manager