The examples here assume the latest supported versions of Shibboleth.
To configure the Shibboleth software to download and verify the signed metadata on at least a daily basis, do the following:
IdP
<!-- inside the ChainingMetadataProvider -->
<MetadataProvider id="ICMD" xsi:type="FileBackedHTTPMetadataProvider" xmlns="urn:mace:shibboleth:2.0:metadata"
metadataURL="http://wayf.incommonfederation.org/InCommon/InCommon-metadata.xml"
backingFile="/opt/shibboleth-idp/metadata/InCommon-metadata.xml">
<MetadataFilter xsi:type="ChainingFilter">
<MetadataFilter xsi:type="RequiredValidUntil" maxValidityInterval="2419200" />
<MetadataFilter xsi:type="SignatureValidation" trustEngineRef="ICTrust" requireSignedMetadata="true" />
<MetadataFilter xsi:type="EntityRoleWhiteList">
<RetainedRole>samlmd:SPSSODescriptor</RetainedRole>
</MetadataFilter>
</MetadataFilter>
</MetadataProvider>
...
<!- underneath the Security Configuration section -->
<security:TrustEngine id="ICTrust" xsi:type="security:StaticExplicitKeySignature">
<security:Credential id="MyFederation1Credentials" xsi:type="security:X509Filesystem">
<security:Certificate>/opt/shibboleth-idp/credentials/incommon.pem</security:Certificate>
</security:Credential>
</security:TrustEngine>
SP
<MetadataProvider type="XML" uri="http://wayf.incommonfederation.org/InCommon/InCommon-metadata.xml"
backingFilePath="InCommon-metadata.xml" reloadInterval="28800">
<!-- Verify with signing key. -->
<SignatureMetadataFilter certificate="incommon.pem"/>
<!-- Require metadata expiration at least monthly. -->
<MetadataFilter type="RequireValidUntil" maxValidityInterval="2419200"/>
</MetadataProvider>