[asterisk-users] fake auth rejection??

[Ira]

Very occasionally in my logs I see things like this. In this case 7 
lines starting with the first line and each ending with one of the 
group of 7. Took about 10 seconds for the 7 tries.

[2012-05-03 16:58:27] NOTICE[31850] chan_sip.c: Sending fake auth 
rejection for device "unknown"

<sip:unknown at 84.246.230.223>;tag=aTZ1eFu5Gi
<sip:unknown at 84.246.230.223>;tag=MQ7X2xPoIy
<sip:unknown at 84.246.230.223>;tag=FnfiJEymn6
<sip:unknown at 84.246.230.223>;tag=tVPso6QAEp
<sip:unknown at 84.246.230.223>;tag=tWHOjRp11z
<sip:unknown at 84.246.230.223>;tag=DK42h3mLn1
<sip:unknown at 84.246.230.223>;tag=CPW3Z9lDvN

Should I be worried?

Ira