Any idea what this is?

I'm seeing this w/tcpdumps at my firewall, I think it began when I
added a Netgear 108MB wireless access point, but Netgear can't tell me
what it is either.

21:52:55.959544 255.89.1.6 > 0.0.6: at-#6 25
21:52:56.059466 255.89.1.6 > 0.0.6: at-#6 25
21:52:56.159496 255.89.1.6 > 0.0.6: at-#6 25
21:52:56.259467 255.89.1.6 > 0.0.6: at-#6 25
21:52:56.359655 255.89.1.6 > 0.0.6: at-#6 25
21:53:01.459349 255.89.1.6 > 0.0.6: at-#6 25
21:53:01.559326 255.89.1.6 > 0.0.6: at-#6 25
21:53:01.659297 255.89.1.6 > 0.0.6: at-#6 25
21:53:01.759333 255.89.1.6 > 0.0.6: at-#6 25
21:53:01.859336 255.89.1.6 > 0.0.6: at-#6 25
21:53:06.959185 255.89.1.6 > 0.0.6: at-#6 25
21:53:07.059166 255.89.1.6 > 0.0.6: at-#6 25
21:53:07.159138 255.89.1.6 > 0.0.6: at-#6 25
21:53:07.259174 255.89.1.6 > 0.0.6: at-#6 25
21:53:07.363115 255.89.1.6 > 0.0.6: at-#6 25

Thanks!