diff --git a/sys/netpfil/pf/pf.c b/sys/netpfil/pf/pf.c
--- a/sys/netpfil/pf/pf.c
+++ b/sys/netpfil/pf/pf.c
@@ -444,6 +444,20 @@
 VNET_DEFINE(uint32_t, pf_hashseed);
 #define	V_pf_hashseed	VNET(pf_hashseed)
 
+#if defined(SCTP) || defined(SCTP_SUPPORT)
+static void
+pf_sctp_checksum(struct mbuf *m, int off)
+{
+	uint32_t sum = 0;
+
+	/* Zero out the checksum, to enable recalculation. */
+	m_copyback(m, off + offsetof(struct sctphdr, checksum),
+	    sizeof(sum), (caddr_t)&sum);
+
+	sctp_delayed_cksum(m, off);
+}
+#endif
+
 int
 pf_addr_cmp(struct pf_addr *a, struct pf_addr *b, sa_family_t af)
 {
@@ -517,6 +531,32 @@
 		m_copyback(m, off, sizeof(*uh), (caddr_t)uh);
 		break;
 	}
+#if defined(SCTP) || defined(SCTP_SUPPORT)
+	case IPPROTO_SCTP: {
+		struct sctphdr *sh = &pd->hdr.sctp;
+		uint16_t checksum = 0;
+		bool rewrite = false;
+
+		if (PF_ANEQ(pd->src, &nk->addr[pd->sidx], pd->af)) {
+			pf_change_ap(m, pd->src, &sh->src_port, pd->ip_sum,
+			    &checksum, &nk->addr[pd->sidx],
+			    nk->port[pd->sidx], 1, pd->af);
+			rewrite = true;
+		}
+		if (PF_ANEQ(pd->dst, &nk->addr[pd->didx], pd->af)) {
+			pf_change_ap(m, pd->dst, &sh->dest_port, pd->ip_sum,
+			    &checksum, &nk->addr[pd->didx],
+			    nk->port[pd->didx], 1, pd->af);
+			rewrite = true;
+		}
+
+		if (rewrite) {
+			m_copyback(m, off, sizeof(*sh), (caddr_t)sh);
+			pf_sctp_checksum(m, off);
+		}
+		break;
+	}
+#endif
 	case IPPROTO_ICMP: {
 		struct icmp *ih = &pd->hdr.icmp;
 
@@ -4453,6 +4493,39 @@
 			}
 			rewrite++;
 			break;
+#if defined(SCTP) || defined(SCTP_SUPPORT)
+		case IPPROTO_SCTP: {
+			uint16_t checksum = 0;
+			bool changed = false;
+
+			if (PF_ANEQ(saddr, &nk->addr[pd->sidx], af) ||
+			    nk->port[pd->sidx] != sport) {
+				pf_change_ap(m, saddr, &pd->hdr.sctp.src_port,
+				    pd->ip_sum, &checksum,
+				    &nk->addr[pd->sidx],
+				    nk->port[pd->sidx], 1, af);
+				sport = pd->hdr.sctp.src_port;
+				pd->sport = &pd->hdr.sctp.src_port;
+				changed = true;
+			}
+			if (PF_ANEQ(daddr, &nk->addr[pd->didx], af) ||
+			    nk->port[pd->didx] != dport) {
+				pf_change_ap(m, daddr, &pd->hdr.sctp.dest_port,
+				    pd->ip_sum, &checksum,
+				    &nk->addr[pd->didx],
+				    nk->port[pd->didx], 1, af);
+				dport = pd->hdr.sctp.dest_port;
+				pd->dport = &pd->hdr.sctp.dest_port;
+				changed = true;
+			}
+
+			if (changed) {
+				pf_sctp_checksum(m, off);
+				rewrite++;
+			}
+			break;
+		}
+#endif
 #ifdef INET
 		case IPPROTO_ICMP:
 			nk->port[0] = nk->port[1];
@@ -5790,6 +5863,7 @@
 	return (PF_PASS);
 }
 
+#if defined(SCTP) || defined(SCTP_SUPPORT)
 static int
 pf_test_state_sctp(struct pf_kstate **state, int direction,
     struct pfi_kkif *kif, struct mbuf *m, int off, void *h,
@@ -5847,8 +5921,37 @@
 
 	(*state)->expire = time_uptime;
 
+	/* translate source/destination address, if necessary */
+	if ((*state)->key[PF_SK_WIRE] != (*state)->key[PF_SK_STACK]) {
+		uint16_t checksum = 0;
+		struct pf_state_key *nk = (*state)->key[pd->didx];
+		bool changed = false;
+
+		if (PF_ANEQ(pd->src, &nk->addr[pd->sidx], pd->af) ||
+		    nk->port[pd->sidx] != pd->hdr.sctp.src_port) {
+			pf_change_ap(m, pd->src, &pd->hdr.sctp.src_port,
+			    pd->ip_sum, &checksum, &nk->addr[pd->sidx],
+			    nk->port[pd->sidx], 1, pd->af);
+			changed = true;
+		}
+
+		if (PF_ANEQ(pd->dst, &nk->addr[pd->didx], pd->af) ||
+		    nk->port[pd->didx] != pd->hdr.sctp.dest_port) {
+			pf_change_ap(m, pd->dst, &pd->hdr.sctp.dest_port,
+			    pd->ip_sum, &checksum, &nk->addr[pd->didx],
+			    nk->port[pd->didx], 1, pd->af);
+			changed = true;
+		}
+
+		if (changed) {
+			m_copyback(m, off, sizeof(pd->hdr.sctp), (caddr_t)&pd->hdr.sctp);
+			pf_sctp_checksum(m, off);
+		}
+	}
+
 	return (PF_PASS);
 }
+#endif
 
 static int
 pf_test_state_icmp(struct pf_kstate **state, int direction, struct pfi_kkif *kif,
@@ -7575,6 +7678,7 @@
 		break;
 	}
 
+#if defined(SCTP) || defined(SCTP_SUPPORT)
 	case IPPROTO_SCTP: {
 		if (!pf_pull_hdr(m, off, &pd.hdr.sctp, sizeof(pd.hdr.sctp),
 		    &action, &reason, AF_INET)) {
@@ -7606,6 +7710,7 @@
 		}
 		break;
 	}
+#endif
 
 	case IPPROTO_ICMP: {
 		if (!pf_pull_hdr(m, off, &pd.hdr.icmp, ICMP_MINLEN,
@@ -8165,6 +8270,7 @@
 		break;
 	}
 
+#if defined(SCTP) || defined(SCTP_SUPPORT)
 	case IPPROTO_SCTP: {
 		if (!pf_pull_hdr(m, off, &pd.hdr.sctp, sizeof(pd.hdr.sctp),
 		    &action, &reason, AF_INET6)) {
@@ -8196,6 +8302,7 @@
 		}
 		break;
 	}
+#endif
 
 	case IPPROTO_ICMP: {
 		action = PF_DROP;