Netgate Discussion Forum
    • Categories
    • Recent
    • Tags
    • Popular
    • Users
    • Search
    • Register
    • Login

    STRANGE CASE?! SYN_SENT:CLOSED Dual-WAN/NAT

    Scheduled Pinned Locked Moved NAT
    4 Posts 3 Posters 3.8k Views
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • B
      biatche
      last edited by

      I have a simple Dual-WAN setup.

      LAN: 192.168.0.254
      WAN: 192.168.201.254 <–DMZ-- .201.1
      OPT1: 192.168.202.254  <--DMZ-- .202.1

      I've setup Policy routing on game source/destination ports / game servers so that all game traffic will go to OPT1 while the default is WAN.

      This case is strange, without initiating traffic through WAN, making connections via OPT1 wouldn't give any response..

      (although I can ping certain hosts via static routes (dns))

      Here's a tcpdump example:
      10:26:57.644458 IP 192.168.0.104.1042 > 74.53.215.6.7456: S 3554463921:3554463921(0) win 65535 <mss 1460,nop,nop,sackok="">10:27:00.507230 IP 192.168.0.104.1042 > 74.53.215.6.7456: S 3554463921:3554463921(0) win 65535 <mss 1460,nop,nop,sackok="">NO RESPONSE (2 packets sent out)

      State: tcp      192.168.0.102:1044 -> 192.168.202.254:1044 -> 74.53.215.6:7456      SYN_SENT:CLOSED

      But after making traffic through WAN, it'll work flawless. Huh?!

      WORKING tcpdump example:
      10:30:21.740800 IP 192.168.0.104.1143 > 74.53.215.6.7456: S 3572235624:3572235624(0) win 65535 <mss 1460,nop,nop,sackok="">10:30:22.024314 IP 74.53.215.6.7456 > 192.168.0.104.1143: S 813763978:813763978(0) ack 3572235625 win 16384 <mss 1452,nop,nop,sackok="">10:30:22.024417 IP 192.168.0.104.1143 > 74.53.215.6.7456: . ack 1 win 65535
      10:30:22.024558 IP 192.168.0.104.1143 > 74.53.215.6.7456: P 1:6(5) ack 1 win 65535

      State: tcp      192.168.0.102:1075 -> 192.168.202.254:1075 -> 74.53.215.6:7456      TIME_WAIT:TIME_WAIT

      ---- What am I doing wrong? Why is it so weird? I even tried deleting all the states related to those hosts involved.. the case is still the same. I'm totally lost.</mss></mss></mss></mss>

      1 Reply Last reply Reply Quote 0
      • C
        cmb
        last edited by

        what pfsense version?

        what interface are you capturing on?

        1 Reply Last reply Reply Quote 0
        • B
          biatche
          last edited by

          latest snapshot.

          i used tcpdump -n …..
          but itll also appear in tcpdump -n -i OPT1nic.... I just didnt use -i cuz i wanted to see the actual source ip

          1 Reply Last reply Reply Quote 0
          • S
            sullrich
            last edited by

            Please make a screenshot of the firewall rules and any related nat rules.

            1 Reply Last reply Reply Quote 0
            • First post
              Last post
            Copyright 2025 Rubicon Communications LLC (Netgate). All rights reserved.