diff --git a/ip/ipxfrm.c b/ip/ipxfrm.c

index 0495ff4..b1d4c6e 100644

--- a/ip/ipxfrm.c

+++ b/ip/ipxfrm.c

@@ -1275,6 +1275,7 @@ static int xfrm_selector_upspec_parse(struct xfrm_selector *sel,

 		case IPPROTO_UDP:

 		case IPPROTO_SCTP:

 		case IPPROTO_DCCP:

+		case IPPROTO_IP: /* to allow shared SA for different protocols */

 			break;

 		default:

 			fprintf(stderr, "\"sport\" and \"dport\" are invalid with PROTO value \"%s\"\n", strxf_proto(sel->proto));