FSO Wifi - can ping but cannot download

[Dylan Semler]

On Mon, Aug 4, 2008 at 6:18 AM, Andy Green <andy at openmoko.com> wrote:

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> Somebody in the thread at some point said:
> | Andy Green escreveu:
> |> Somebody in the thread at some point said:
> |> | I've configured WiFi on a fresh FSO image the same way I had on a
> 2008.2
> |> | image--by creating a wpa_supplicant.conf file and editing
> |> | /etc/network/interfaces.  This configuration worked on the 2008.2
> image
> |> | but when I try implementing it on an FSO image, I cannot download
> |> | anything.  I can ping sites and when using wget, I can connect to
> them,
> |> | but downloading never commences.  It's not a DNS issue because ping
> and
> |> | wget seem to be able to resolve correctly.  Any thoughts?
> |>
> |> Sounds specific to tcp transport, ping is ICMP and DNS usually UDP.
> |> Maybe connect to a local Linux box and run tcpdump on there to study
> |> what it sees from the connection action.
> |
> | No, it's not "ping and DNS do not use TCP". It's "ping and DNS and TCP
> | SYN are small packets, data transfer is large packets", i.e. PMTU
> | blackhole. I've seen that thing happen way too many times, and the
> | workaround is almost always a MSS clamp (which is an ugly but
> | unfortunately necessary hack).
>
> Well, he says it worked on some other image.
>
> The guy can test this by seeing if he has any bulk transfer with local
> machines on his side of his router.
>
> He can also mess with his ping payload size and confirm if that controls
> the issue...
>
> # ping -s 4096 192.168.0.1
> PING 192.168.0.1 (192.168.0.1) 4096(4124) bytes of data.
> 4104 bytes from 192.168.0.1: icmp_seq=1 ttl=64 time=5.36 ms
>


I can wget files hosted on the local side of the router, cannot wget
anything external.  ping -s 4096 192.168.1.1 still works.

-- 
Dylan

Type faster. Use Dvorak:
http://dvzine.org
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