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iPhone name server lookup: “Unknown server error” for

# ping
ping: cannot resolve Unknown server error
# nslookup

Non-authoritative answer: canonical name =

This is one of the known problems on the iPhone. The same thing happens when libCURL in SyncEvolution tries to resolve the name. Visting the site in Safari “fixes” the problem for a while, but sooner or later it has a very unwelcome comeback. Strangely enough, it only affects and not

One user reported that he had the same problem and that pinging the site helped, but I cannot reproduce that. Any other suggestions?

Update 2007-11-28: good news for users of ScheduleWorld – since November 27th ScheduleWorld moved off of a CNAME and onto a dedicated A record. This was done to avoid the name server lookup problems on the iPhone. Thanks Mark!

{ 7 } Comments

  1. Nikki Chumakov | November 14, 2007 at 2:33 pm | Permalink

    As a working workaround you can put the ip+name of into /etc/hosts.

    However the content of /etc/hosts does not survive reboots.

    Any suggestions?

    Ok, may syncevolution application add the needed record into /etc/hosts on the start?

  2. Patrick Ohly | November 14, 2007 at 7:31 pm | Permalink

    Nikki, I had used the same workaround and was going to propose that as a solution (well, kind of). I had not yet rebooted, so I wasn’t aware of the fact that the setting gets lost – bummer.

    I suppose syncevolution could add the setting, but which one? The IP address might change and I don’t want to update the binary just because of that. It just doesn’t smell right.

  3. Nikki Chumakov | November 15, 2007 at 12:08 am | Permalink

    It would be nice if IP address can be placed in config file, not hardcoded in binary. I’m aware that IP can be changed of course. Then one will have to reflect this change in config. It is not nice, but better than nothing.


  4. Patrick Ohly | November 15, 2007 at 5:48 pm | Permalink

    The configured IP address still needs to be in /etc/hosts because libCURL (although inside the syncevolution binary) will always read it from there or DNS.

    If possible I’d like to avoid messing with that file in SyncEvolution code. Perhaps an iPhone startup script can be written which adds user-configurable entries to /etc/hosts on each boot.

    I had started to investigate this issuse by taking network dumps of the name server lookup, but the results were inconclusive. I suppose I need to continue this work to really identify the relevant difference between (which always seems to work) and I’m traveling right now and won’t have time before next week, though.

    There’s one more thing that could be tested (but I doubt that it’ll work): setting the fixed IP address in the syncevolution config instead of The reason why I expect this to fail is that the server’s response will probably redirect the client to the normal name. It is worth a test, though. Anyone willing to try it and prove me wrong? ;-)

  5. Patrick Ohly | February 10, 2008 at 3:45 pm | Permalink

    To those who still have in /etc/hosts: the IP address has changed, remove the entry. It hasn’t been needed since Mark changed the ScheduleWorld DNS setup anyway.

    On my iPhone (1..02 firmware) the entry survived reboots and I had completely forgotten about it when syncing failed with “Error in preparing sync: libcurl error 7, couldn’t connect to host”…

  6. Olivier | February 16, 2008 at 2:12 am | Permalink

    I’ve just upgraded to 1.1.3 and the SyncEvolution plugin doesn’t work! I’m entering my username and passord into the settings, and when I close it reverts back to the guest account… any idea?

  7. Patrick Ohly | February 16, 2008 at 9:14 am | Permalink

    Olivier, this is a problem of the Funambol GUI, not of SyncEvolution. I’m afraid I cannot do anything about it; you’ll have to contact Funambol.

    As a workaround you could try setting up a SyncEvolution configuration manually as explained on estamos’ Installation page.

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