SIP Attack？

NVR500でFusion IP-Phoneを使ってるんですが
変な着信記録が残ってた



それでログを見たら
[SIPGW Rcv] To [192.168.0.1:5060] From [62.210.146.81:5062]
[SIPGW Rcv] SIP_REQUEST[INVITE]
[SIPGW Snd] To [62.210.146.81:5062] From [192.168.0.1:5060]
[SIPGW Snd] SIP_RESPONSE[100]
[SIP] SIP Call from [sip:100@1.1.1.1] to [sip:100@192.168.0.1] rejected.
[SIPGW Snd] To [62.210.146.81:5062] From [192.168.0.1:5060]
[SIPGW Snd] SIP_RESPONSE[404]

これがSIP ATTACKなのかな？
http://www.rtpro.yamaha.co.jp/RT/FAQ/Security/sip_trouble.html

無言電話対策はしてるけど
http://www.rtpro.yamaha.co.jp/RT/FAQ/VoIP/troublevoip-ans.html#10のセキュアフィルターも設置しとく