You need a high metric null route for that /32. Liam Farr wrote:

Hi,I'verunintoabitofadumbproblem,hopefullysomeoneherecanpointmeintherightdirection.Ireceivearoutetoa/28fromamemberofmyBGPconfederation,(the/28isonadirectlyconnectedinterfaceofthisrouter)viaBGPtooneofmyedgerouters,andIwishtoadvertiseaspecific/32fromthis/28toanexternalBGPpeer(upstreamprovider)fromthisedgerouter.Icanuseroute-mapsandprefix-lists,todefineaBGPexportpolicytoonlyexportthe/32totheexternalneighborwithoutissue.WhereIgetstuckisgettingthe/32intomyroutetable,essentiallyIneedtode-aggregatethe/28downtoa/32?Isthereanaccepted"bestpractice"wayofdoingthis?Apologiesifthisisastupidquestion,I'veneverrunintothisissuebefore,andGoogleisn'tgivingmemuchhelp.CheersLiamFarr