[Exim] Exim: Interpretting exim log. What is wrong here?

Dear Group,

I have the following on my exim/log/mainlog. I am trying to interpret what
this exacly means and why I am getting these? Is someone trying to route the
mail thru my mail server.

H=irm-4-13.dialup.access.telecore.net.ru (xx.xx.xxx.yy) [213.135.70.108]
F=<some-user-name@???> rejected RCPT <another-user-name@???>: relay
not permitted

Where xx.xx.xxx.yy is one of my ips (eth0:0)

Thanks,
Prince.