no udp response on FreeBSD/arm

Vernon Schryver
Sun Jun 24 14:33:43 UTC 2012

> From: "Ronald Klop" <>

> I am trying to run dccproc/dccifd on FreeBSD-9/arm. I get no response on  
> the UDP request. I suspected firewall issues so I tried it on my desktop  
> FreeBSD-9/amd64 and there everything works well.
> The output of ngrep looks different on the same e-mail.

The DCC client-server protocol is purely binary and involves no
text.  Every request and response packet, including retransmissions
of a request, should have a unique combination of transaction ID
and other bits.

I think there was once an Ethereal DCC decoder.  A recent Wireshark
DCC decoder seems to understand at least some DCC requests from
clients but responses from servers not so much.  I've never used
either one.

>                                                         I don't know what  
> to think about that, but maybe the udp packet is 'corrupted' on arm.
> Is this a known issue?

It's news to me.

>                        What can I provide to debug this?

I would first check for an IPFW firewall on the FreeBSD-9/arm system.
Then I would try:

   `cdcc info`

    cdcc "host; rtt"

    see if cdcc and then dccproc can talk to a DCC server running on
     the local machine.  If that works, then my guess would involve
     compiler or kernel network bugs.

Vernon Schryver

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