FIRST SUPPLEMENT AND AMENDMENT
                               TO TRUST INDENTURE

         THIS FIRST  SUPPLEMENT  AND  AMENDMENT TO TRUST  INDENTURE  dated as of
February 1, 2001 ("First Indenture  Supplement")  among The Bank of New York, as
Trustee,   and  DTI  Holdings,   Inc.,  a  Missouri   corporation,   as  Issuer,
supplementing  and amending the Indenture  dated as of February 23, 1998 between
DTI  Holdings,  Inc.  as Issuer and The Bank of New York as Trustee  relating to
$506,000,000  aggregate  principal  amount at maturity  12 1/2% Senior  Discount
Notes due 2008 and 12 1/2% Series B Senior Discount Notes due 2008.

                                    RECITALS

A.       The Issuer and the Trustee have  entered into an Indenture  dated as of
         February 23, 1998 relating to $506,000,000  aggregate  principal amount
         at maturity 12 1/2% Senior Discount Notes due 2008 and 12 1/2% Series B
         Senior Discount Notes due 2008 (the "Existing Indenture").

B.       Capitalized  terms  used  herein which are not otherwise defined herein
         shall  have  the meanings set forth in Section 101 of the Indenture (as
         defined in the Existing Indenture).

C.       The Issuer is proposing to acquire for cash the Outstanding Notes which
         have  been  validly  tendered  to it if at  least  a  majority  of  the
         aggregate  principal  amount  of the  Notes  at  Maturity  are  validly
         tendered and not withdrawn  prior to the expiration  date of the tender
         offer.

D.       In connection with the actions  described in the immediately  preceding
         Recital,  the Issuer and Trustee desire to amend the Existing Indenture
         immediately prior to the acceptance of the Notes pursuant to the tender
         offer upon the receipt of the  consents of the Holders of not less than
         the  majority  in  aggregate  principal  amount  at  Maturity  of  then
         Outstanding Notes (the "Requisite Consent").

E.       Section 902 of the Existing  Indenture  authorizes  the Trustee and the
         Issuer,  when  authorized  by a  Board  resolution,  to  enter  into an
         Indenture  supplemental  to the Existing  Indenture  on  obtaining  the
         Requisite Consent.

F.       The Requisite Consent has been obtained and all other actions desirable
         or  required  by  the  Existing  Indenture  or  otherwise necessary and
         desirable to effect the amendment have been taken.

                                    AGREEMENT

         Accordingly,  in consideration of the premises and the mutual covenants
herein contained and for other good and valuable consideration,  the receipt and
sufficiency of which are hereby acknowledged,  the parties hereto agree that the
Existing Indenture shall be amended and supplemented as follows:




         1.       Amendments

                  (a) Section 101 of the Existing Indenture is amended effective
as of the date hereof (y) by deleting the definitions of Existing  Subsidiaries,
Permitted   Indebtedness,   Permitted   Investments   and  Permitted  Liens  and
substituting in lieu thereof the following new definitions:

                  "Existing  Subsidiaries"   mean   Digital  Teleport,  Inc.,  a
         Missouri  corporation,  and  Digital  Teleport  of  Virginia,  Inc.,  a
         Virginia  corporation and  wholly owned subsidiary of Digital Teleport,
         Inc.

                  "Permitted Indebtedness" means any of the following:

                           (a)   Indebtedness of the Company  pursuant  to   the
         Notes;

                           (b)   Indebtedness   of  the  Company  owing  to  any
         Restricted Subsidiary (but only so long as such Indebtedness is held by
         such  Restricted  Subsidiary);  provided that any  Indebtedness  of the
         Company  owing to any such  Restricted  Subsidiary is  subordinated  in
         right of payment from and after such time as the Notes shall become due
         and payable (whether at Stated Maturity,  by acceleration or otherwise)
         to the payment and performance of the Company's  obligations  under the
         Notes;  provided  further  that any  transaction  pursuant to which any
         Restricted  Subsidiary to which such Indebtedness is owed, ceases to be
         a Restricted  Subsidiary  shall be deemed to be an  incurrence  of such
         Indebtedness  by such  Restricted  Subsidiary  that is not permitted by
         this clause (b);

                           (c)  Indebtedness  of the  Company or any  Restricted
         Subsidiaries  consisting of  guarantees,  indemnities or obligations in
         respect of purchase price  adjustments  in connection  with one or more
         credit facilities permitted under clause (j), clause (k) and clause (l)
         of  this  definition  or  in  connection  with  the  acquisition  of or
         disposition of assets, including, without limitation, shares of Capital
         Stock;

                           (d)  Indebtedness  of the  Company or any  Restricted
         Subsidiary  under letter of credit  facilities that are used to finance
         trade  payables  in the  ordinary  course of  business  and under which
         recourse to the Company or any Restricted  Subsidiary is limited to the
         cash securing such letters of credit;

                           (e)  Indebtedness  of the  Company or any  Restricted
         Subsidiary  under  Currency  Agreements  and Interest  Rate  Agreements
         entered into in the ordinary  course of  business;  provided  that such
         agreements do not increase the Indebtedness of the obligor  outstanding
         at any time other than as a result of fluctuations in foreign  currency
         exchange rates or interest rates or by reason of fees,  indemnities and
         compensation payable thereunder;

                           (f)  Indebtedness  of the  Company or any  Restricted
         Subsidiary  in addition to that  permitted  to be incurred  pursuant to
         clauses (a) through (e) above in an aggregate  principal  amount not in

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         excess of  $25,000,000  (or,  to the extent not  denominated  in United
         States dollars, the United States Dollar Equivalent thereof) at any one
         time outstanding;

                           (g)  Purchase Money Indebtedness;

                           (h)  Indebtedness of any Restricted Subsidiary to the
         Company;

                           (i)  Prior to December 31, 2000,  Indebtedness of the
         Company or any  Restricted  Subsidiary  not to exceed,  at any one time
         outstanding,  two  times  (A) the Net  Cash  Proceeds  received  by the
         Company after the date of this Indenture as a capital  contribution  or
         from the issuance and sale of its  Qualified  Capital Stock to a Person
         that is not a Subsidiary  of the  Company,  to the extent such Net Cash
         Proceeds  have not been used  pursuant to clause  (a)(3)(B)  or clauses
         (b)(ii) and (iii) of Section 1009 to make a Restricted  Payment and (B)
         80% of the fair  market  value of  property  (other  than cash and Cash
         Equivalents)  received by the Company after the date of this  Indenture
         as a contribution of capital or from the sale of its Qualified  Capital
         Stock to a  Person  that is not a  Subsidiary  of the  Company,  to the
         extent such capital contribution or sale of Qualified Capital Stock has
         not been used  pursuant to clause  (a)(3)(B)  of Section 1009 to make a
         Restricted  Payment;  provided that such  Indebtedness  does not mature
         prior to the  Stated  Maturity  of the  Notes and has an  Average  Life
         longer than the Notes;

                           (j)  Indebtedness  of the  Company or any  Restricted
         Subsidiary  under one or more facilities  outstanding at any time in an
         aggregate principal amount not to exceed (i) $70,000,000, plus (ii) the
         greater of (x) 80% of the  accounts  receivable  of the  Company or (y)
         $30,000,000;

                           (k)  Indebtedness  of the  Company,  the  proceeds of
         which are to be used to acquire  some or all of the Notes  tendered for
         cash, in an aggregate  principal  amount not to exceed (i) $94,000,000,
         plus (ii) interest payable in connection therewith;

                           (l)  Indebtedness of the Company  or  any  Restricted
         Subsidiary outstanding at any time in an aggregate principal amount not
         to exceed $100,000,000; and

                           (m)  any   renewals,    extensions,    substitutions,
         refinancings  or  replacements  (each,  for purpose of this  clause,  a
         "refinancing") of any Indebtedness of the Company (including all or any
         part of the Notes) or any Restricted  Subsidiary by the Company, or any
         refinancing of any  Indebtedness  of any Restricted  Subsidiary by such
         Restricted Subsidiary,  including any successive refinancings,  so long
         as in  the  case  of  Indebtedness  other  than  Indebtedness  incurred
         pursuant  to clauses  (b)  through (f) and (h) through (l) (i) any such
         new  Indebtedness  shall be in a principal  amount that does not exceed
         the  principal  amount  (or,  if  such  Indebtedness  being  refinanced
         provides for an amount less than the principal amount thereof to be due
         and payable upon a declaration  of  acceleration  thereof,  such lesser
         amount as of the date of determination) so refinanced,  plus the amount
         of any premium  reasonably  determined as necessary to accomplish  such

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         refinancing  and the amount of  expenses  of the  Company  incurred  in
         connection with such  refinancing,  (ii) in the case of any refinancing
         of Subordinated Indebtedness, such new Indebtedness is made subordinate
         to the  Notes at least to the same  extent  as the  Indebtedness  being
         refinanced,  (iii) in the case of any refinancing of Indebtedness  that
         is pari passu in right of payment with the Notes, such new Indebtedness
         is made pari passu in right of payment with, or subordinate in right of
         payment  to,  the  Notes  and  (iv)  (A)  if  such  Indebtedness  being
         refinanced  has an Average  Life longer  than the  Average  Life of the
         Notes,  such new  Indebtedness  has an  Average  Life  longer  than the
         Average  Life of the Notes and a final Stated  Maturity  later than the
         final Stated Maturity of the Notes and (B) if such  Indebtedness  being
         refinanced  has an Average  Life  shorter  than the Average Life of the
         Notes,  such  Indebtedness has an Average Life longer than, and a Final
         Stated Maturity Date later than, such Indebtedness being so refinanced.

                  "Permitted Investments" means any of the following:

                           (a)  Investments in Cash Equivalents;

                           (b)  Investments in the  Company  or  any  Restricted
         Subsidiary;

                           (c)  Investments  by the  Company  or any  Restricted
         Subsidiary in another  Person,  if as a result of such  Investment  (i)
         such other Person  becomes a Restricted  Subsidiary  and the Company or
         another Restricted  Subsidiary owns at least 66 2/3% of the outstanding
         Voting  Stock of such other  Person or (ii) such other Person is merged
         or  consolidated   with  or  into,  or  transfers  or  conveys  all  or
         substantially  all  of its  assets  to,  the  Company  or a  Restricted
         Subsidiary;

                           (d)  Acquisition of any Notes up to and including
         100% of  the  aggregate  principal  amount at Maturity of the  original
         Outstanding Notes;

                           (e)  Investments  by the  Company  or any  Restricted
         Subsidiary in any Person  engaged in the delivery of telephony or other
         telecommunications  or data transmission services in North America, the
         sum of which does not exceed  $20,000,000 at any one time  outstanding;
         or

                           (f)  Investments in existence on  the  date  of  this
         Indenture.

                  "Permitted Liens" means the following types of Liens:

                           (a)  Liens existing as of the date of the issuance of
         the Notes;

                           (b)  Liens on any property or assets of a  Subsidiary
         granted in favor of the Company or any Restricted Subsidiary;

                           (c)   Liens securing the Notes;

                           (d)   any interest or title of  a  lessor  under  any
         Capitalized Lease Obligation or of a seller  under any  Purchase  Money
         Indebtedness permitted by this Indenture;


                                       4


                           (e)   Liens  securing  Indebtedness  incurred   under
         clause (j),  clause  (k)   and   clause   (l) of   the   definition  of
         "Permitted Indebtedness";  provided  that the  Liens  in  the  case  of
         clauses (k) and (l) shall be  limited to  Capital  Stock of any one  or
         more Restricted Subsidiaries of the Company;

                           (f)   statutory  Liens or  landlord's  and carrier's,
         warehouseman's,  mechanic's, supplier's, materialmen's,  repairmen's or
         other like Liens  arising in the  ordinary  course of business and with
         respect to amounts not yet delinquent or being  contested in good faith
         by appropriate proceeding, if a reserve or other appropriate provision,
         if any, as shall be required  in  conformity  with GAAP shall have been
         made therefor;

                           (g)   Liens   for   taxes,   assessments,  government
         charges or claims that are being contested in good faith by appropriate
         proceedings  promptly  instituted  and  diligently  conducted  and if a
         reserve or other appropriate provision, if any, as shall be required in
         conformity with GAAP shall have been made therefor;

                           (h)   Liens  incurred  or  deposits  made  to  secure
         the performance of tenders, bids, leases, statutory obligations, surety
         and appeal bonds,  government  contracts,  performance  bonds and other
         obligations   of  a  like  nature   (including,   without   limitation,
         indefeasible rights to use) incurred in the ordinary course of business
         (other than contracts for the payment of money);

                           (i)   easements,      servitudes,      rights-of-way,
         restrictions (including,  without limitation,  zoning restrictions) and
         other similar charges or  encumbrances  not interfering in any material
         respect with the business of the Company or any Subsidiary  incurred in
         the ordinary course of business;

                           (j)   Liens  arising  by  reason  of  any   judgment,
         decree or order of any court so long as such Lien is adequately  bonded
         and any appropriate legal proceedings that may have been duly initiated
         for the review of such  judgment,  decree or order  shall not have been
         finally  terminated or the period within which such  proceedings may be
         initiated shall not have expired;

                           (k)   Liens securing  Acquired  Indebtedness  created
         prior  to  (and  not in  connection  with or in  contemplation  of) the
         incurrence  of such  Indebtedness  by the  Company  or any  Subsidiary;
         provided  that such Lien does not extend to any  property  or assets of
         the  Company  or any  Subsidiary  other  than the  assets  acquired  in
         connection with the incurrence of such Acquired Indebtedness;

                           (l)   Liens   securing   Interest  Rate Agreements or
         Currency Agreements  permitted to be incurred pursuant to clause (e) of
         the  definition of "Permitted  Indebtedness"  or any collateral for the
         Indebtedness  to  which  such  Interest  Rate  Agreements  or  Currency
         Agreements relate;

                                       5


                           (m)   Liens arising from  purchase  money   mortgages
         and purchase  money security  interests;  provided that (i) the related
         Indebtedness  shall not be  secured  by any  property  or assets of the
         Company  or any  Subsidiary  other  than the  property  and  assets  so
         acquired  (and  proceeds  thereof)  and  (ii) the  Lien  securing  such
         Indebtedness shall be created within 60 days of such acquisition;

                           (n)   Liens with respect  to  assets of a  Restricted
         Subsidiary  granted by such  Restricted  Subsidiary to the Company or a
         Restricted  Subsidiary to secure  Indebtedness  owing to the Company or
         such Restricted Subsidiary;

                           (o)   pledges  and  deposits  made  in  the  ordinary
         course  of  business  in   connection   with   workers'   compensation,
         unemployment insurance and other types of statutory obligations; and

                           (p)   any   extension,   substitution,   renewal   or
         replacement,  in  whole  or in  part,  of  any  Lien  described  in the
         foregoing  clauses  (a)  through  (o)  or  any  successive   extension,
         substitution, renewal or replacement; provided that any such extension,
         substitution,  renewal or replacement  shall be no more  restrictive in
         any material respect than the Lien so extended, substituted, renewed or
         replaced and shall not extend to any additional property or assets.

                  and (z) by adding the following new definitions:

                           "First Indenture Supplement" means that certain First
         Supplement  and Amendment to Trust  Indenture,  dated as of February 1,
         2001 amending and supplementing the Indenture.

                           "KLT" means KLT Telecom Inc., a Missouri corporation.

                           (b) The Existing Indenture is amended effective as of
         the  date  hereof  by  deleting  paragraph  (i) of  Section  801 in its
         entirety and  substituting  in lieu thereof the following new paragraph
         (i):

                                    (i)  either  (a)  the  Company  will  be the
                  continuing  corporation  or (b) the  Person (if other than the
                  Company)  formed  by  such  consolidation  or into  which  the
                  Company  or such  Subsidiary  is  merged or the  Person  which
                  acquires  by  sale,  conveyance,   transfer,  lease  or  other
                  disposition,  all or  substantially  all of the properties and
                  assets of the Company and its  Subsidiaries  on a consolidated
                  basis  substantially  as an entirety,  as the case may be (the
                  "Surviving  Entity"),  (1) will be a  corporation  or  limited
                  liability  company  organized and validly  existing  under the
                  laws of the United States of America, any state thereof or the
                  District  of  Columbia  and (2) will  expressly  assume,  by a
                  supplemental  indenture to this Indenture in form satisfactory
                  to the Trustee, the Company's obligation pursuant to the Notes
                  for the due and punctual  payment of the principal  (including
                  accretion of original issue discount) of, premium,  if any, on
                  and  interest  on  all  the  Notes  and  the  performance  and

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                  observance of every  covenant of this Indenture on the part of
                  the Company to be  performed or observed  provided  however if
                  the Surviving  Entity is a Subsidiary the Company may continue
                  to be obligated on the Indenture;

                           (c) The Existing Indenture is amended effective as of
         the date hereof by adding  thereto the  following  new paragraph (c) to
         Section 1009:

                                    (c)  Notwithstanding  anything  contained in
                  this Section 1009 hereof to the  contrary  (without  affecting
                  any  restriction  contained in Section 1015 of the Indenture),
                  the  Company  and  its  Restricted  Subsidiaries  may  use the
                  proceeds   from  any  sales,   leases,   transfers   or  other
                  dispositions of assets to prepay any debt described in clauses
                  (j), (k) or (l) of the definition of Permitted Indebtedness or
                  the Notes.

                           (d) The Existing  Indenture  is amended  effective as
         the  date  hereof  by  deleting   Section  1016  in  its  entirety  and
         substituting in lieu thereof the following new Section 1016:

                  The  Company  will not,  and will not  permit  any  Restricted
                  Subsidiary  to,  directly or  indirectly,  create or otherwise
                  cause or suffer to exist or become  effective any  encumbrance
                  or  restriction  of any kind on the ability of any  Restricted
                  Subsidiary to (a) pay dividends, in cash or otherwise, or make
                  any other distributions on or in respect of its Capital Stock,
                  (b) pay any  Indebtedness  owed to the  Company  or any  other
                  Restricted Subsidiary,  (c) make Investments in the Company or
                  any  other  Restricted  Subsidiary,  (d)  transfer  any of its
                  properties  or assets to the  Company or any other  Restricted
                  Subsidiary or (e) guarantee any Indebtedness of the Company or
                  any other Restricted Subsidiary,  except for such encumbrances
                  or  restrictions  existing  under  or by  reason  of  (i)  any
                  agreement in effect on the Issue Date,  (ii)  applicable  law,
                  (iii)  customary   non-assignment   provisions  of  any  lease
                  governing  a   leasehold   interest  of  the  Company  or  any
                  Restricted Subsidiary,  (iv) any agreement or other instrument
                  of  a  Person  acquired  by  the  Company  or  any  Restricted
                  Subsidiary in existence at the time of such  acquisition  (but
                  not created in contemplation  thereof),  which  encumbrance or
                  restriction is not applicable to any Person, or the properties
                  or  assets  of any  Person,  other  than  the  Person,  or the
                  property  or  assets  of the  Person,  so  acquired,  (v)  the
                  refinancing  of  Indebtedness  incurred  under the  agreements
                  existing on the Issue Date,  so long as such  encumbrances  or
                  restrictions  are no less favorable in any material respect to
                  the Company or any Restricted  Subsidiary than those contained
                  in the  respective  agreement  as in effect on the Issue Date,
                  (vi)   restrictions   contained  in  any  security   agreement
                  (including a capital lease obligation)  securing  Indebtedness
                  of the Company or a Restricted  Subsidiary otherwise permitted
                  under this Indenture, (vii) customary nonassignment provisions
                  entered into in the ordinary  course of business in leases and
                  other  agreements,  (viii) any  restriction  with respect to a
                  Restricted Subsidiary of the Company entered into for the sale
                  or  disposition  of all or  substantially  all of the  Capital
                  Stock  or  assets  of  such  Restricted   Subsidiary  made  in

                                       7


                  accordance  with Section 1015, (ix) pursuant to this Indenture
                  and the Notes,  (x)  Permitted  Indebtedness  permitted  under
                  clause  (j),  clause  (k) or  clause  (l)  of  the  definition
                  thereof,  so long as such  encumbrances or restrictions do not
                  prevent  dividends or other  distributions on or in respect of
                  the Capital Stock of a Restricted Subsidiary of the Company to
                  be used  by the  Company  to make  principal  or  interest  or
                  premium (if any)  payments  on the Notes when due  (whether at
                  Stated  Maturity,  by acceleration or otherwise),  or (xi) any
                  agreement or instrument  governing or relating to Indebtedness
                  under any  senior  commercial  bank  facility  (each,  a "Bank
                  Facility") if such encumbrance or restriction  applies only to
                  (A) amounts which at any point in time (other than during such
                  periods as are  described  in the  following  clause  (B)) (1)
                  exceed amounts due and payable (or which are to become due and
                  payable  within  30  days)  in  respect  of the  Notes or this
                  Indenture for interest,  premium and principal or (2) if paid,
                  would result in an event described in the following clause (B)
                  of this sentence, or (B) during the pendency of any event that
                  causes, permits or, after notice or lapse of time, would cause
                  or permit the holder(s) of Indebtedness  governed by such Bank
                  Facility to declare such  Indebtedness  to be immediately  due
                  and payable or to require cash collateralization or cash cover
                  for   such   Indebtedness   for   so   long   as   such   cash
                  collateralization or cash cover has not been provided.

         2.       Miscellaneous.

                  (a)      Except as expressly amended and supplemented  hereby,
                           the  Existing  Indenture  shall  continue  to be, and
                           shall remain,  in full force and effect in accordance
                           with its terms,  and this First Indenture  Supplement
                           shall not be deemed to be a waiver  of, or consent to
                           any  supplement  or  amendment  of, any other term or
                           condition of the Existing Indenture.

                  (b)      This First  Indenture  Supplement  may be executed by
                           the parties hereto in separate counterparts,  each of
                           which  when so  executed  and  delivered  shall be an
                           original,   while  all  such  counterparts   together
                           constitute but one and the same instrument.

                  (c)      This First Indenture Supplement shall in all respects
                           be governed by, and construed in accordance with, the
                           laws of the State of New York.


                                       8




         IN WITNESS WHEREOF, the parties hereto have caused this First Indenture
Supplement  to be duly  executed by their  respective  officers  thereunto  duly
authorized as of the day and year first above written.

                                       DTI HOLDINGS, INC.




                                       By:  /s/ Gary W. Douglass
                                            ------------------------------------
                                               Name:  Gary W. Douglass
                                               Title: Senior Vice President
                                                      Finance and Administration
                                                      Chief Financial Officer


                                       THE BANK OF NEW YORK, Trustee




                                       By:  /s/ Robert A. Massimillo
                                            ------------------------------------
                                                      Signatory





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