[hpsdr] Metis/Hermes: what to do if a wrong IP is programmed
Andrea Montefusco
andrea.montefusco at gmail.com
Wed Nov 6 16:00:19 PST 2013
Hi all,
I don't know if this issue has already been signaled here, in case please point me to the right thread.
Yesterday I was showing my Metis to a friend of mine, and I decided to program a static IP address
over it: I was successful, using the HPSDRProgrammer (on Windows XP SP3).
After my little demo, I restarted the system and programmed again the "all ones" address; next I
cycled the power and the Metis became strangely unreachable.
So, I decided to take a trace with tcpdump: the Metis was not even attempting to do DHCP, however in
the trace the usual discovery packet was there, as well the answer from Metis, but, apparently, the
software was not able to process or even receive a perfectly good answer packet.
After some head scratching, looking better to the trace I discovered that the Metis IP was
255.255.255.0
instead of
255.255.255.255
So what happened was that I incorrectly wrote a "0" in the last octet field and this went
undetected both by HPSDRProgrammer and Metis' firmware.
Now, several sources over Internet say that Windows discards that packet (a packet with the source
address starting with 255) because that address range (class E in the dark ages) has been defined
'reserved' long time ago, so that explain the behavior above.
Of course I was able to recover setting the J1 jumper and using HPSDRBootloader: that would have
been not so simple in case of Hermes/ANAN systems, where one has to open the box in order to set the
jumper.
I think we should filter that incorrect or reserved addresses, at least into HPSDRProgrammer.
*am*
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Andrea Montefusco iw0hdv (ex FAI10655) http://www.montefusco.com
tel: +393356992791 fax: +390623318709
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