freebsd-net Digest, Vol 181, Issue 9

Mon Sep 18 04:49:40 PDT 2006

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Today's Topics:

   1. Re: FreeBSD 6.1 + ath0 + NAT (Sam Leffler)
   2. Re: iwi discarding oversized packets while mtu=1500 for
      src/dst (Sam Leffler)
   3. Re: NIC Problems (pauls at utdallas.edu)
   4. Re: Can someone take a look at PR 89061 (ipv6 autoconfigure
      6to4) (gnn at freebsd.org)
   5. Re: problems with ng_fec (Michael W. Lucas)
   6. Re: ppp command port does not listens on ipv4 unless no INET6
      in kernel (Hajimu UMEMOTO)

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Message: 1
Date: Sat, 16 Sep 2006 09:06:11 -0700
From: Sam Leffler 
Subject: Re: FreeBSD 6.1 + ath0 + NAT
To: Phil Chadwick 

Cc: freebsd-net at freebsd.org
Message-ID: <450C20F3.2000005 at errno.com>
Content-Type: text/plain; charset=ISO-8859-1

Phil Chadwick wrote:
> Hi all,
> 
> This is my first post, so please be gentle :-)
> 
> I have a Linksys WAG54G V.2 ADSL modem (Firmware Version: 1.00.39)
> connection to the Internet, and a Netgear WG311T wireless Ethernet card
> running on FreeBSD 6.1 (PC#1).
> 
> Recently I added a second FreeBSD 6.1 system (PC#2) which has no
> wireless card (well it does, but it's a TI chipset not supported in
> FreeBSD).  So I connected it to PC#1 with a Gigabit copper wire
> connection.  I also added firewall and NATing on PC#1 to provide PC#2
> with a route to the Internet.
> 
> When I boot PC#1, the connection between ath0 and the ADSL modem will run
> as expected (routing to the Internet for itself and PC#2) for some time
> (roughly anywhere from 0 to 30 minutes), but always eventually hangs.
> It's then not possible to ping the ADSL modem.

Do you really mean you ping the modem or a host on the far side of the
modem?

> 
> The hang happens regardless of whether the new (PC#2) system is booted
> or not.

Then ignore PC#2 and remove it from the system.

> 
> The PC#1 ath0 wireless connection has been woking flawlessly (without
> the firewall and NAT changs) for nearly a year (originally under FreeBSD
> 6.0 with Sam Lefflers ath patches) and more recently on FreeBSD 6.1.
> 
> Can anybody spot anything obviously wrong with the new setup, or know of
> any bug reports that might impact a NATing gateway on a wireless connection?
> 
> I have also recently discovered the link goes up and down every 20 or 30
> minutes with what looks like a DHCP lease renewal.  This extracted from
> /var/log/messages:
> 
> Sep 13 19:42:21 kt400 kernel: ath0: link state changed to DOWN
> Sep 13 19:42:23 kt400 kernel: ath0: link state changed to UP
> Sep 13 19:42:23 kt400 dhclient: New IP Address (ath0): 192.168.1.64
> Sep 13 19:42:23 kt400 dhclient: New Subnet Mask (ath0): 255.255.255.0
> Sep 13 19:42:23 kt400 dhclient: New Broadcast Address (ath0): 192.168.1.255
> Sep 13 19:42:23 kt400 dhclient: New Routers (ath0): 192.168.1.1
> Sep 13 20:12:21 kt400 kernel: ath0: link state changed to DOWN
> Sep 13 20:12:23 kt400 kernel: ath0: link state changed to UP
> Sep 13 20:12:23 kt400 dhclient: New IP Address (ath0): 192.168.1.64
> Sep 13 20:12:23 kt400 dhclient: New Subnet Mask (ath0): 255.255.255.0
> Sep 13 20:12:23 kt400 dhclient: New Broadcast Address (ath0): 192.168.1.255
> Sep 13 20:12:23 kt400 dhclient: New Routers (ath0): 192.168.1.1
> Sep 13 21:32:21 kt400 kernel: ath0: link state changed to DOWN
> Sep 13 21:32:24 kt400 kernel: ath0: link state changed to UP
> 
> Looks like a smoking gun?  Is this likely to upset the firewall/NATing?

Unlikely.

> 
> [I have not yet had a chance to correlate the hang with the lease renewal,
> but will test that tomorrow.]
> 
> In the kernel config file I have added:
> 
> options IPFIREWALL
> options IPDIVERT
> 
> In /etc/rc.conf I have:
> 
> # See also /etc/wpa_supplicant.conf
> ifconfig_ath0="WPA DHCP"
> # Private x-over to printer
> ifconfig_rl0="inet kt400pr netmask 255.255.255.0 broadcast 10.0.0.255"
> # Private x-over to Dell 350 (PC#2)
> ifconfig_sk0="inet gbkt400 netmask 255.255.255.0 broadcast 192.168.2.255"
> # These added for firewall/NATing
> gateway_enable="YES"
> firewall_enable="YES"
> firewall_type="OPEN"
> natd_enable="YES"
> natd_interface="ath0"
> natd_flags=""
> 
> [kt400.145] cat /etc/wpa_supplicant.conf
> network={
>     ssid="linksys"
>     key_mgmt=NONE
>     wep_key0=xxxxxxxxxx
>     wep_tx_keyidx=0
> }
> 
> [kt400.146] ifconfig -a
> sk0: flags=8843 mtu 1500
> options=8
> inet6 fe80::215:e9ff:feb0:e5b0%sk0 prefixlen 64 scopeid 0x1
> inet 192.168.2.1 netmask 0xffffff00 broadcast 192.168.2.255
> ether 00:15:e9:b0:e5:b0
> media: Ethernet autoselect (none)
> status: no carrier
> 
> ath0: flags=8843 mtu 1500
> inet6 fe80::20f:b5ff:fef6:28eb%ath0 prefixlen 64 scopeid 0x2
> inet 192.168.1.64 netmask 0xffffff00 broadcast 192.168.1.255
> ether 00:0f:b5:f6:28:eb
> media: IEEE 802.11 Wireless Ethernet autoselect (DS/11Mbps)
> status: associated
> ssid linksys channel 11 bssid 00:14:bf:7a:57:94
> authmode OPEN privacy ON deftxkey 1 wepkey 1:40-bit txpowmax 37
> protmode CTS burst roaming MANUAL bintval 100
> 
> rl0: flags=8843 mtu 1500
> options=8
> inet6 fe80::220:edff:fe70:471a%rl0 prefixlen 64 scopeid 0x3
> inet 10.0.0.254 netmask 0xffffff00 broadcast 10.0.0.255
> ether 00:20:ed:70:47:1a
> media: Ethernet autoselect (none)
> status: no carrier
> 
> fwe0: flags=108802
 mtu 1500
> options=8
> ether 02:00:20:71:b9:a6
> ch 1 dma -1
> lo0: flags=8049 mtu 16384
> inet6 ::1 prefixlen 128
> inet6 fe80::1%lo0 prefixlen 64 scopeid 0x5
> inet 127.0.0.1 netmask 0xff000000
> 
> 
> Thanks,
> 
> 

I am confused about what the config is and what exactly is wrong.  Try
simplifying your configuration so you can pinpoint the problem.  It
sounds like you've got a sta associated to an ap using ath.  That sta
cannot pass packets beyond the ap after some period of time.  Have you
look on the ap to see if packets are still flowing?  Have you used
tcpdump to look for packets on the far side of the ap (on the wired
network)?

 Sam

Hi Phil,
Just adding my 2cents for wat it's worth. Did you check the routing table to see if the DHCP renewal with the link going up and down is causing any problems ?. Also, have you made sure there is no other aps or stations on the same channel which could be causing your link to go up and down ?.

nayak

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