Duet Ethernet when ping -a no network name only IP address

  • But on Wifi units this works correctly.

  • The processing for the "-a" flag on Windows "ping" occurs entirely on Windows; no data (for the -a request itself) is sent to or from the IP being pinged. The "-a" flag causes Windows to attempt a "reverse name lookup", that is, it starts with the IP address specified, and attempts to derive a hostname (in the TCP/IP sense of hostname, which is actually an interface name).

    The exact way that windows does this is long and complex, and actually varies depending on several Windows configuration items, and on the presence or absence of a DNS (domain name server), and even a few other things... Therefore I will not try to describe it. Google it, and you can find many pages of detail.

    One thing is for ABSOLUTE certain in that whole reverse lookup sequence, the device being pinged absolutely does not participate in the reverse name lookup in any way. There is nothing the device could do, or not do, or whatever, to cause -a to produce a name, or not produce a name.


    Whatever on YOUR network, and/or windows machine, causes the IP address of the Ethernet Duet to fail in a "reverse-lookup" name resolution, and also causes the WiFi Duet IP address to succeed in a "reverse lookup" name resolution... whatever that is, it is NOT the printers. It literally cannot be.

    If you wish to pursue this... google how ping really works (ICMP echo) and how name resolution (forward) works. Once that is solid in your mind, then begin to look at how reverse name resolution works. Lots and lots of documentation out there...

  • administrators

    There is some info at https://social.technet.microsoft.com/Forums/en-US/8a0346de-2296-4f46-bc36-ff3fb13e283b/builtin-mdnsdnssd-zeroconf-support-in-windows-10?forum=win10itpronetworking. Basically, it says that MDNS support is still not available in Win32 unless you install Bonjour or a similar service.

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