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| | <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable" xlink:label="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_1"/> |
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| | <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProductOrServiceAxis" xlink:label="loc_us-gaap_ProductOrServiceAxis_2"/> |
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| | <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="loc_us-gaap_ProductsAndServicesDomain_3"/> |
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| | <loc xlink:type="locator" xlink:href="idt-20160731.xsd#idt_WholesaleCarrierServicesMember" xlink:label="loc_idt_WholesaleCarrierServicesMember_5"/> |
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| | <loc xlink:type="locator" xlink:href="idt-20160731.xsd#idt_HostedPlatformSolutionsMember" xlink:label="loc_idt_HostedPlatformSolutionsMember_7"/> |
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| | <loc xlink:type="locator" xlink:href="idt-20160731.xsd#idt_ConsumerPhoneServicesMember" xlink:label="loc_idt_ConsumerPhoneServicesMember_8"/> |
| | <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductsAndServicesDomain_3" xlink:to="loc_idt_ConsumerPhoneServicesMember_8" order="40" use="optional"/> |
| | <loc xlink:type="locator" xlink:href="idt-20160731.xsd#idt_FabrixSubsidiaryMember" xlink:label="loc_idt_FabrixSubsidiaryMember_9"/> |
| | <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductsAndServicesDomain_3" xlink:to="loc_idt_FabrixSubsidiaryMember_9" order="50" use="optional"/> |
| | <loc xlink:type="locator" xlink:href="idt-20160731.xsd#idt_ZedgeMember" xlink:label="loc_idt_ZedgeMember_10"/> |
| | <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductsAndServicesDomain_3" xlink:to="loc_idt_ZedgeMember_10" order="60" use="optional"/> |
| | <loc xlink:type="locator" xlink:href="idt-20160731.xsd#idt_RealEstateServiceMember" xlink:label="loc_idt_RealEstateServiceMember_11"/> |
| | <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductsAndServicesDomain_3" xlink:to="loc_idt_RealEstateServiceMember_11" order="70" use="optional"/> |
| | <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_12"/> |
| | <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_0" xlink:to="loc_us-gaap_Revenues_12" order="10" use="optional"/> |
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| | <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EntityWideRevenueMajorCustomerLineItems" xlink:label="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_0"/> |
| | <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable" xlink:label="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_1"/> |
| | <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_0" xlink:to="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_1" order="0" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true"/> |
| | <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="loc_us-gaap_StatementGeographicalAxis_2"/> |
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| | <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_3"/> |
| | <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementGeographicalAxis_2" xlink:to="loc_us-gaap_SegmentGeographicalDomain_3" order="0" use="optional"/> |
| | <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_3_Default"/> |
| | <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementGeographicalAxis_2" xlink:to="loc_us-gaap_SegmentGeographicalDomain_3_Default" order="0" use="optional"/> |
| | <loc xlink:type="locator" xlink:href="idt-20160731.xsd#idt_OtherCountriesMember" xlink:label="loc_idt_OtherCountriesMember_4"/> |
| | <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_3" xlink:to="loc_idt_OtherCountriesMember_4" order="0" use="optional"/> |
| | <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2016/country-2016-01-31.xsd#country_GB" xlink:label="loc_country_GB_5"/> |
| | <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_3" xlink:to="loc_country_GB_5" order="10" use="optional"/> |
| | <loc xlink:type="locator" xlink:href="idt-20160731.xsd#idt_EntityWideDisclosureOnGeographicAreasRevenueFromExternalCustomersAttributedToForeignCountriesPercentage" xlink:label="loc_idt_EntityWideDisclosureOnGeographicAreasRevenueFromExternalCustomersAttributedToForeignCountriesPercentage_6"/> |
| | <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_0" xlink:to="loc_idt_EntityWideDisclosureOnGeographicAreasRevenueFromExternalCustomersAttributedToForeignCountriesPercentage_6" order="10" use="optional"/> |
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| | <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:label="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_0"/> |
| | <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:label="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_1"/> |
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| | <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="loc_us-gaap_StatementGeographicalAxis_2"/> |
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| | <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_3"/> |
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| | <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_3_Default"/> |
| | <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementGeographicalAxis_2" xlink:to="loc_us-gaap_SegmentGeographicalDomain_3_Default" order="0" use="optional"/> |
| | <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2016/country-2016-01-31.xsd#country_US" xlink:label="loc_country_US_4"/> |
| | <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_3" xlink:to="loc_country_US_4" order="0" use="optional"/> |
| | <loc xlink:type="locator" xlink:href="idt-20160731.xsd#idt_ForeignCountriesMember" xlink:label="loc_idt_ForeignCountriesMember_5"/> |
| | <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_3" xlink:to="loc_idt_ForeignCountriesMember_5" order="10" use="optional"/> |
| | <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NoncurrentAssets" xlink:label="loc_us-gaap_NoncurrentAssets_6"/> |
| | <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_0" xlink:to="loc_us-gaap_NoncurrentAssets_6" order="10" use="optional"/> |
| | <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_7"/> |
| | <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_0" xlink:to="loc_us-gaap_Assets_7" order="20" use="optional"/> |
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