wireless access point in FreeBSD 8.2p2

Bill Tillman btillman99 at yahoo.com
Sun Aug 28 19:38:48 UTC 2011

From: Paul Beard <paulbeard at gmail.com>
Cc: "freebsd-questions at FreeBSD. ORG" <freebsd-questions at freebsd.org>
Sent: Sunday, August 28, 2011 12:22 PM
Subject: Re: wireless access point in FreeBSD 8.2p2

On Aug 28, 2011, at 7:04 AM, CyberLeo Kitsana wrote:

> It is especially useful when you cannot ping, as it can tell you if the
> packets are even arriving.

The "no route to host" result makes me think the packets aren't going far ;-) The new device and the wired interface are at adjacent numeric addresses and all the devices here are in the same subnet behind the WRT54G and that is behind the cable co's black box. 

I think I may be more confused now than when I started. 

One thing that has seemed opaque to me is that both ath0 and wlan0 display when I run ifconfig and look very similar: makes me think they might be stepping on each other. Or it's just one more thing I don't understand :-( 

ath0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 2290
    ether 00:0d:88:93:21:3a
    media: IEEE 802.11 Wireless Ethernet autoselect mode 11g <hostap>
    status: running

wlan0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
    ether 00:0d:88:93:21:3a
    inet netmask 0xffffff00 broadcast
    inet6 fe80::20d:88ff:fe93:213a%wlan0 prefixlen 64 scopeid 0x8 
    nd6 options=3<PERFORMNUD,ACCEPT_RTADV>
    media: IEEE 802.11 Wireless Ethernet autoselect mode 11g <hostap>
    status: running
    ssid lower channel 8 (2447 MHz 11g) bssid 00:0d:88:93:21:3a
    regdomain FCC indoor ecm authmode OPEN privacy OFF txpower 27
    scanvalid 60 protmode CTS wme burst dtimperiod 1 -dfs

I know (or think I do) that ath0 is the real interface and wlan0 is a virtualized or cloned or something handle to it. But the similarities (both are running, both show the same info for media) trouble me. The only thing that makes me think I'm doing anything here is that wlan0 is actually assigned to channel 8. 

I can sort of see that getting it working as a client would be instructive and I think I did that some time ago (perhaps in 7.x) but since you reuse almost nothing but the hardware, I don't see a lot of value in that, other than verifying that the hardware works and that you can follow the instructions. The latter can be a challenge, I'll admit. 

So to recap: the idea of this was to provide a redundant spare for the WRT54G, behind a cable modem, in a private network, with the only security being at the AP
    • No ipfw or any of that, as it wouldn't be visible on the public internet.
    • I'll add WPA/2 once it works (that seems trivial, as I have been able to authenticate to the AP even though it didn't pass any packets beyond that). 
    • It would deal with static addresses (I could add dhcp later, once this was working, as phones and other devices are more easily dealt with that way). So it looks like a bridge, if it joins an Ethernet network and an 802.11-based one. Curiously, none of the instructions I have seen mention bridging, even though the explicitly connect Ethernet and wireless. And all the HOWTOs look simple, the work of a few minutes of copy and paste. 

I think I may just shelve this and if needed, turn up my Time Capsule's wireless capability (if it would play nicely and extend the WRT54G, I'd be using it now). And APs that support open source firmware are not that hard to find, though Tomato doesn't support as many as the *-wrt variants. 


Paul Beard

Are you trying to win an argument or solve a problem? 

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It's been about 18 months since I went through this exercise with FreeBSD but I found it to be not worth the effort. I spent several hours getting all the configs right and the docs were as usual out of date but I eventually got it going. The trouble was it was sporadic at best. Sometimes the laptop clients made the connection and other times they didn't. And when they did the speed of the wireless connection was so slow, it just wasn't worth my time.

I did this to have the experience with it and to have a backup to my Netgear wireless router. The trouble was the Netgear wireless AP device works so well and is plenty fast, unlike what I was getting with my FreeBSD server. The Netgear device has been working 24/7 for almost 2 years now so I just gave up on the  FreeBSD option. I would like to think that things are better now, I just haven't had the time to take another whack at it.

Good luck.

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