User alert, user intrusion throwing me off the internet

Hey guys,

i am am having a issue with my router and iMac that is driving me mental. Every time I connect to my sky router on my iMac the Internet stops working after a couple of seconds. At first I thought it might be my Mac so I reset wifi settings and other settings to no avail. My next step was to wipe the Mac and try a fresh install but I noticed something on the sky routers log that appears every time I try connect to my wifi.the log report is as follows:

user.alert kernel: Intrusion -> IN=pppoa0 OUT= MAC= SRC=61.160.224.130 DST=90.192.237.178 LEN=40 TOS=0x00 PREC=0x00 TTL=242 ID=54321 PROTO=TCP SPT=33443 DPT=32764 WINDOW=65535 RES=0x00 SYN URGP=0 MARK=0x8000000

I have tried to research this and found something about the router blocking connections that try find unsecured connects and that the routers doing its job.

I find it strange that it seems to be blocking my iMac. Can anyone give me any advice on any way to fix this or other things it could be.

also we have other macs and devices on the network and all connect fine.

thanks,
matthew