Multiple Simultaneous VPN Tunnels cause HUGE slowdown, dropped packets

  • Hello.

    I have set up PFSense at one facility, and ZyWALL 5 units at two remote facilities.

    I can have either remote facility connected via IPSEC VPN and i get around 20ms latency,
    no dropped packets, high throughput (300kbps)

    If i enable the 2nd facility's vpn connection, i start dropping packets on BOTH vpn tunnels,
    and the ping times rise from 20ms to 100+ ms.

    I ensured that the identifiers are different, and event went so far to have different
    pre-shared keys, encryption algorithms, etc.

    Please help me understand whether this is a limitation of racoon, a pfsense specific issue,
    perhaps a hardware issue, or just a configuration problem?

    I am trying to eliminate the point to point T1s my company currently uses and implement
    cable with dsl backup, so (for me at least), this has a sense of urgency.

    Thank you for your help!


  • Are you watching bandwidth utilization when this occurs and sure that your pipe isn't filling up when the IPsec connection to the 2nd facility comes up for some reason?

  • Hey Guys

    I'm seeing something very similar. I have 3 tunnels and and intermittently I cannot ping through the tunnel, it's really odd, it's causing me all sorts of problems. Is there something I can post up here  that may help identify the problem.

    I don't think bandwidth is an issue for me as I have a 10Mb symmetrical link the tunnels are going over.

  • Hello all.

    I am not sure what I did to fix the issue (if anything at all) but it seems OK now.

    I believe i was able to see that the racoon process was dying, so I just rebooted the whole box, and only ran 1 tunnel for a while.  Then one night I was playing with the configurations, testing, doing some file transfers etc etc and it all seems OK..?

    to ensure it was really stable i ran 1 million pings at 100ms interval on both tunnels simultaneously (takes around a day), and I lost around 0.01% of the packets, averaging around 20ms round trip.

    Sorry I can't really help anyone else out there, i guess my only suggestion is play with the encryption settings, identifiers, etc etc..


  • Good to hear yours is ok.

    Well I've been running for just over 24 hours and mine has been fine as well, I might try the ping test my self and test how stable it is. The only real difference between now and my last post is that I did have a duplex issue on my WAN that was fixed and have since reinstalled and loaded up the old config, and all is good so far.


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