Asix ax88772b problems

  • pfsense 2.1.5, a fresh install.  The problem is weird enough that I double checked about five times and finally reinstalled from scratch just to try to make sure that I'm not doing something moronic.

    I've been trying to get a USB NIC (Asix ax88772b ) to work.  I'm not concerned about throughput, I realize people have had some difficulty with that.

    These USB NICs should be recognized by the axe driver, and, seem to be.  From dmesg:

    axe0: <vendor 4="" 0x0b95="" product="" 0x772b,="" rev="" 2.00="" 0.01,="" addr="">on usbus2
    miibus2: <mii bus="">on axe0
    ue0: <usb ethernet="">on axe0</usb></mii></vendor> 

    I mostly used the USB as the LAN address, although I tried it as the WAN and had the same issue.  If used as the LAN, machines below would pull dhcp addresses from the USB NIC, and if used as WAN the box itself can pull a DHCP address.  In either case I am able to ping out using IPs, but anything else fails.  I cannot perform a DNS lookup over the USB NIC.  I cannot browse to a website, even using the IP.  I cannot ssh out.  I don't think that this could be a fail with firewall rules because If I use a different interface as WAN it can do any of these things without a hitch.

    Here's an example tcpdump (on the pfsense box) of trying to do a DNS request from a machine connected to ue0 via DHCP at

    18:19:07.932593 IP (tos 0x0, ttl 128, id 22394, offset 0, flags [none], proto UDP (17), length 67) > [udp sum ok] 1+ PTR? (39)
    18:19:07.932911 IP (tos 0x0, ttl 64, id 62589, offset 0, flags [none], proto UDP (17), length 67, bad cksum 0 (->6dc7)!) > [udp sum ok] 1 NXDomain q: PTR? 0/0/0 (39)
    18:19:09.939810 IP (tos 0x0, ttl 128, id 22395, offset 0, flags [none], proto UDP (17), length 70) > [udp sum ok] 2+ A? (42)
    18:19:10.117204 IP (tos 0x0, ttl 64, id 17644, offset 0, flags [none], proto UDP (17), length 145, bad cksum 0 (->1d0b)!) > 2 NXDomain q: A? 0/1/0 ns: . SOA[|domain]
    18:19:11.942652 IP (tos 0x0, ttl 128, id 22396, offset 0, flags [none], proto UDP (17), length 58) > [udp sum ok] 3+ A? (30)
    18:19:11.942993 IP (tos 0x0, ttl 64, id 65146, offset 0, flags [none], proto UDP (17), length 74, bad cksum 0 (->63c3)!) > [udp sum ok] 3 q: A? 1/0/0 A (46)

    To make this whole thing even more bizzare, on FreeBSD 8.3 I have no such problem.  The USB NICs work without a hitch.  Does anyone know what's going on here?


  • I've been using this for a while now:
    Ugreen 20241 USB 2.0 to 10/100Mbps Ethernet
    It is built around ASIX AX88772A (your's is a B)

    I gave up troubleshooting it. It just can't work consistently with a dynamic IP (with pfSense and any flavor of FreeBSD I tried).
    So, I configured it with static IP on the LAN side and it has been completely trouble free.


  • When configured as LAN it was static.  I didn't have any trouble with that configuration on FreeBSD.

  • Netgate Administrator

    Not sure if we ever got to the bottom of this. Can you compare the ifconfig output from pfSense with that of FreeBSD? Could this be hardware off-loading? TCP is not working but UDP is.


  • Steve,

    In my case it's been a dynamic IP issue. I went back to using it with a dynamic IP for testing again. On the WAN side everything gets going flawlessly and works for a variable amount of time. In one case it was as short as 3-4 minutes, in the best case it worked fine for almost 2 hours. Then suddenly no access to the Internet as the WAN IP is lost. pfSense seems to work fine otherwise, as LAN to LAN routing, etc. are all ok. When the failure happens there is very little information in the logs, almost none!
    Neither from the webGUI nor from the console one can renew the WAN IP (the function just hangs), it requires a complete restart of pfSense (either from the WebGUI or from the console).

    On FreeBSD 8.x and 9.x the same thing happens. (Dynamic IP, normal DHCP client config) Except for the fact that everything seems to work a little longer before failure. While testing FreeBSD I tried 3 different DHCP servers (linux based, windows based and from a commercial router) Same outcome!

    But when the interface is set to use a static IP all the problems go away and the adapter works flawlessly. I can actually drive it almost full speed (>90 megabit per second) It doesn't drop a single packet for days at a time. (Remember I've been using this thing for many months now on the LAN side of my pfSense router)

    Everything above is pretty much what I mentioned in earlier posts. The only new input is that I also tested (this time really thoroughly) this adapter on Windows (XP, Vista, Server 2003 and 7) and Debian Linux (and its derivatives like Ubuntu and LinuxMint).
    This adapter works so well that it would put to shame all those who have been badmouthing USB/Ethernet adapters for so long on these forums.