iwi discarding oversized packets while mtu=1500 for src/dst

[Hans Nieser]

Sam Leffler wrote:
> Hans Nieser wrote:
>> Hi,
>>
>> Today I wanted to go back to using FreeBSD on my laptop, which is still
>> installed but hasn't been used for several months because I am still
>> waiting for a stable Intel HDA driver. So I performed a full upgrade of my
>> installed ports. However I ran into an issue that prevented me from
>> logging in to my FreeBSD server over ssh.
...
>> My server's NIC:
>> xl0 at pci2:0:0:   class=0x020000 card=0x10001458 chip=0x920010b7 rev=0x78
>> hdr=0x00
>>     vendor   = '3COM Corp, Networking Division'
>>     device   = '3C905C-TX Fast EtherLink for PC Management NIC'
>>     class    = network
>>     subclass = ethernet
>>
>> Laptop's NIC:
>> iwi0 at pci1:3:0:  class=0x028000 card=0x27018086 chip=0x42208086 rev=0x05
>> hdr=0x00
>>     vendor   = 'Intel Corporation'
>>     device   = 'PRO/Wireless 2200BG Network Connection'
>>     class    = network

> I see none of the basic info needed to help.  OS version?  description
> of how the device is setup (e.g. ifconfig cmds) and current
> state--ifconfig iwi0.

Apologies, some extra info as requested (and some ASCII-art because I was
bored!):

The Laptop's WLAN NIC is connected to an AP integrated into my DSL device
(specifically, it's a Thompson SpeedTouch 716WL). My server's NIC is
connected over UTP to the 4-port switch also integrated into the DSL
device. So basically:

 _____________
|             |
| (Intarwebs) |
|_____________|
   |
 __|______________________
|      ___________________|
|     |         |         |
| DSL | LAN hub | WLAN AP |
|_____|_________|_________|
           |         |
       ____|___      |            ________
      |        |     |           |        |
      | Server |       ~ ~ ~ ~ ~ | Laptop |
      |________|                 |________|

The wireless AP is configured to only allow 802.11g devices and uses
WPA-PSK for security with TKIP encryption.

Laptop setup ---------------------------------------------------------

root at aphax-laptop:~# uname -a
FreeBSD aphax-laptop.lan 6.1-RELEASE FreeBSD 6.1-RELEASE #0: Thu May 11
07:17:09 CEST 2006
root at aphax-laptop.nieser.local:/usr/obj/usr/src/sys/APHAX-LAPTOP  i386

root at aphax-laptop:~# ifconfig iwi0
iwi0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet6 fe80::215:ff:fe2b:20ab%iwi0 prefixlen 64 scopeid 0x2
        inet 192.168.1.65 netmask 0xffffff00 broadcast 192.168.1.255
        ether 00:15:00:2b:20:ab
        media: IEEE 802.11 Wireless Ethernet autoselect (OFDM/54Mbps)
        status: associated
        ssid geendraadjes channel 8 bssid 00:11:f5:ca:50:71
        authmode WPA privacy ON deftxkey UNDEF TKIP 2:128-bit txpowmax 100
        protmode CTS roaming MANUAL bintval 100

root at aphax-laptop:~# cat /etc/rc.conf | grep -B 4 ifconfig
hostname="aphax-laptop.lan"
network_interfaces="lo0"
#ifconfig_sk0="DHCP"
ifconfig_iwi0="DHCP WPA"

root at aphax-laptop:~# cat /etc/wpa_supplicant.conf
network={
        ssid="nieser"
        psk="xxxxxxxxxx"
}

network={
        ssid="niba"
        psk="xxxxxxxxxx"
}

network={
        ssid="geendraadjes"
        psk="xxxxxxxxx"
}

Server setup ---------------------------------------------------------

root at mishmash:~# uname -a
FreeBSD mishmash.geendraadjes 6.1-RELEASE FreeBSD 6.1-RELEASE #0: Sat May
13 03:02:19 CEST 2006
root at mishmash.geendraadjes:/usr/obj/usr/src/sys/MISHMASH  i386

root at mishmash:~# ifconfig xl0
xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        options=9<RXCSUM,VLAN_MTU>
        inet6 fe80::20a:48ff:fe0f:40c7%xl0 prefixlen 64 scopeid 0x1
        inet 192.168.1.1 netmask 0xffffff00 broadcast 192.168.1.255
        ether 00:0a:48:0f:40:c7
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active

root at mishmash:~# cat /etc/rc.conf | grep -B 2 ifconfig
defaultrouter="192.168.1.254"
hostname="mishmash.lan"
ifconfig_xl0="inet 192.168.1.1  netmask 255.255.255.0"