ssh connects to originating host

[Geoffrey Leach]

Two systems A and B, connected via wireless. A and B both have the same 
/etc/hosts. Connecting from B to A, "ssh A", works fine. However on A, 
"ssh B" logs me into A. This used to work fine; the only clue I have is 
that ssh did not like the stored RSA key. I let it fix it, and that's 
when the trouble started. Rebooting A did not fix, nor did removing the 
saved key and repeating.

Any suggestions?

Thanks.