diff --git a/lib/call-session.js b/lib/call-session.js
index 412193b..4fffa30 100644
--- a/lib/call-session.js
+++ b/lib/call-session.js
@@ -6,7 +6,8 @@ const {
   SdpWantsSDES,
   nudgeCallCounts,
   roundTripTime,
-  parseConnectionIp
+  parseConnectionIp,
+  isPrivateVoipNetwork
 } = require('./utils');
 
 const {forwardInDialogRequests} = require('drachtio-fn-b2b-sugar');
@@ -177,7 +178,7 @@ class CallSession extends Emitter {
         ...this.rtpEngineOpts.common,
         ...this.rtpEngineOpts.uac.mediaOpts,
         'from-tag': this.rtpEngineOpts.uas.tag,
-        direction:  ['public', 'private'],
+        direction:  [isPrivateVoipNetwork(this.req.source_address) ? 'private' : 'public', 'private'],
         sdp
       };
       const startAt = process.hrtime();
diff --git a/lib/utils.js b/lib/utils.js
index 6dfb849..0a4bcd1 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -195,6 +195,14 @@ const isMSTeamsCIDR = (ip) => {
   return matcher.contains(ip);
 };
 
+const isPrivateVoipNetwork = (ip) => {
+  if (process.env.PRIVATE_VOIP_NETWORK_CIDR) {
+    const matcher = new CIDRMatcher(process.env.PRIVATE_VOIP_NETWORK_CIDR.split(','));
+    return matcher.contains(ip);
+  }
+  return false;
+};
+
 module.exports = {
   isWSS,
   SdpWantsSrtp,
@@ -211,5 +219,6 @@ module.exports = {
   nudgeCallCounts,
   roundTripTime,
   parseConnectionIp,
-  isMSTeamsCIDR
+  isMSTeamsCIDR,
+  isPrivateVoipNetwork
 };