From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin Bangiev Subject: DNAT & SNAT delay Date: Tue, 14 Jun 2005 12:13:37 +0300 Message-ID: <42AE9FC1.6050204@borsabg.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: netfilter-bounces@lists.netfilter.org Errors-To: netfilter-bounces@lists.netfilter.org Content-Type: text/plain; charset="us-ascii"; format="flowed" To: netfilter@lists.netfilter.org Hi guys, I have two applications based in different networks that has to communicate with each other using many small UDP packets. Due to security reasons I set the firewall for SNAT and DNAT dynamically. Here is the exact situation. Client1: IP - 10.0.0.2 Client2: IP - 172.16.0.2 Firewall: IP1 - 10.0.0.1 IP2 - 172.16.0.1 Client1 sends it's datagrams to the Firewall:IP1 Client2 sends it's datagrams to the Firewall:IP2 Just before the communication starts I add rules to DNAT udp packets from Client1 to Client2, and to SNAT packets to Client2 to be from Firewall:IP2. I do it for the Client2 respective (of course I set up the ports too). The problem is that the NAT starts with about 30 seconds delay. tcpdump shows the packets are coming from Client1 but they are not SNATed & DNATed. The counters of the rules however counts the packets. Once the packets begin to be NATed the counters stops. Can you please tell me where this delay can be coming from? Thanks in advance:)