diff --git a/ipa/IPA_Test.ttcn b/ipa/IPA_Test.ttcn
index c8b8205..d15c50f 100644
--- a/ipa/IPA_Test.ttcn
+++ b/ipa/IPA_Test.ttcn
@@ -46,6 +46,9 @@
 	PortNumber mp_msc_port := 5000;
 	charstring mp_msc_ip := "127.0.0.1";
 
+	PortNumber mp_nat_port := 5000;
+	charstring mp_nat_ip := "127.0.0.1";
+
 	charstring mp_sccp_service_type := "mtp3_itu";
 
 	integer mp_bsc_pc := 196;
@@ -110,7 +113,7 @@
 	for (i := 0; i < NUM_BSC; i := i+1) {
 		f_init_BscState(bsc[i], mp_bsc_pc +i, mp_msc_pc, mp_bsc_ssn, mp_msc_ssn);
 		bsc[i].BSC := BSC_CT.create;
-		bsc[i].BSC.start(BSC_MS_Simulation.main(mp_msc_ip, mp_msc_port, mp_bsc_ip, mp_bsc_port+i,
+		bsc[i].BSC.start(BSC_MS_Simulation.main(mp_nat_ip, mp_nat_port, mp_bsc_ip, mp_bsc_port+i,
 							bsc[i].sccp_pars, bsc[i].sccp_addr_own,
 							bsc[i].sccp_addr_peer));
 	}