Administration Target

An iMac Intel Core 2 Duo:

  • Mac OS X 10.6.6;
  • ARD Client 3.4-current;

Router Configuration

  • WAN-side TCP & UDP 22, 3283 and 5900 forwarded to the iMac.
  • In desperation, I DMZed the administration target.


Before DMZing my administration target (i.e., with only 22, 3283 and 5900 forwarded), the iMac is listed as "Offline" on the Remote Desktop administration screen. However, I can ssh into it from Terminal.app successfully and I can control the screen — I simply can't do any 'special' tasks (copy, install, report, restart, sleep, etc): I essentially can't do anything other than viewing/controlling (and locking) the screen.

Once the host was DMZed, my administration window lists the node as "Screen Sharing Only".

Any ideas?

  • Are you sure the RDP administrator software isn't trying to use ping or something similar to determine if the target is up? It might be worth checking to see if your router is discarding icmp echo messages, which could confuse the RDP admin software.
    – Fake Name
    Feb 14, 2011 at 7:30
  • That was, indeed, my first thought, and the first thing I checked. Thank you for suggesting it, though!
    – msanford
    Feb 18, 2011 at 13:59
  • @Fake Name make your comment an answer and I'll close the question. ;)
    – msanford
    Feb 18, 2011 at 14:54

1 Answer 1


Does The ARD Administrator client use a ping (ICMP_ECHO) to determine client status?

A lot of firewalls silently swallow echo requests, even of the host is up. Therefore, you may be getting false reports about host status.

  • It does indeed use an icmp_echo_request to determine if the host is up or not.
    – msanford
    Feb 20, 2011 at 18:08

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