PfSense very slow on TCP open

  • I'm having a problem with all of my TCP services (like HTTP and SMTP). There is a NAT rule that maps the WAN side public address to the DMZ and a firewall rule that lets it through. With packet capture on both sides you can see the open come in the public interface and a full 10 seconds later come out the DMZ side. By them some mail servers have timed out. Any idea why it would have this problem or where to start looking.



  • Hi

    Any dns issues around? Because 10 sec delay is something like dns' time-out.


  • This is a good question and I'm not sure of the answer. I have 4 DNS servers. 2 are private 2 are public. The private server do recursive lookups, so these are the ones I have specified. They are on a LAN subnet.

    The fact is that I don't know what pfSense needs in terms of DNS. I could simply give it public servers, but then anything specific to the internal zones will fail lookup. If I give it private servers I'm not sure if it expects them to be on a specific interface or what rules it might need to see them.


  • Yes, it looks like it was (is) a DNS problem. Mail server is trying to do a reverse lookup on the source address… which just happens to be one of my public subnets that I'm decommissioning. So the DNS query to the internal server tried to go out and back in to the public server and just kind of dies there. It seems like its just affecting my testing.


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