I've just enabled dkim and in the DNS records for the domain I see there are actually multiple keys advertised, e.g.
IN TXT ( "v=DKIM1; k=rsa; t=s; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA1LCXtFGavrgJ0" "DvDXcDFiT2IYEBAknLt5dhncLnBMI4ZY4fJ4Et9N3GRpIgKfkOXkH0FYCfcCNGijgB2UN2w98stf3XXD" "m0/kUOpX2fp4JHmUjcjv0hmZWavRvrEvCL8YU7/Vm/cnRN1lGHjUG6QDAyHkR947gSFkXpiz6xQRZjYM" "KZRn/rQPArLosXv1HCw+PllV+rC3NLDZ7CiNc38/OPOPYUKVjRvg9CXqSSj1zfmFPocStvYguFtgwiPc" "td2IQhbQGk9cm/621BzohG1GCo3WobhUVJCONFL/QAKVNVy0Bdc1h8wEV1GeqTAn+qrxPSWFxsTiOrz/" "dczzej47QIDAQAB" )
Why are there multiple keys there? Shouldn't it be just the one? Also, my DNS is actually external to the server and I can't add all of them. Which one is the valid one?