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--- hardware:gatewaynetflow [2019/01/03 17:38] – [IPTABLES Port based NAT] veera
+++ hardware:gatewaynetflow [2019/01/03 18:34] – [Reference] veera
@@ Line 13: / Line 13: @@
 ==== Shutdown ufw or disable firewalld ====
+since we are working directly with iptables.
 <code  bash>
@@ Line 31: / Line 32: @@
 <code>
-$ iptables -t nat -A PREROUTING -p udp --dport 2055 -j DNAT --to-destination 10.10.10.17:2055
+$ iptables -t nat -A PREROUTING -p udp \
-$ iptables -t nat -A POSTROUTING -j MASQUERADE
+    --dport 2055 -j DNAT --to-destination 10.10.10.17:2055
 </code>
@@ Line 39: / Line 40: @@
-==== Reference ====
+<note important>NOTE: Do not use the MASQUERADE POSTROUTING rule, because we want to preserve the Source IP address of the original router in the netflow packets. Otherwise Trisul can  assume that the Gateway device is the router.
+</note>
+==== Useful commands ====
-How to redirect incoming traffic on a port to another IP [[[https://my.esecuredata.com/index.php?/knowledgebase/article/49/how-to-redirect-an-incoming-connection-to-a-different-ip-address-on-a-specific-port-using-iptables/|link]]]
+To view NAT rules with counters
+''
+iptables -t nat -vL
+''
+==== Reference ====
+Forwarding and NAT  with IPTABLES : Redhat https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/4/html/Security_Guide/s1-firewall-ipt-fwd.html