Check my two FW logs

Please check my two CIS’s firewall logs. I will be happy If someone explain me why are there a connection attempts with port 1900, and ICMP Type 3 and why my computer thinks that he is a router (sending IGMP to “all”)?

Both computers using same internet connection, but aren’t in any other LAN or sharing relation. Both are malware free.

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The UDP’s on 1900 are SSDP (Windows Service) looking for upstream devices.

ICMP type 3. It’s hard to say without knowing the context, but these are probably Destination host/port unreachable being returned to in response to another application (which is not handling ICMP’s itself, eg. P2P).

The IGMP’s to are IGMPv3 Multicast report messages (specifically RFC3376)… things like the Windows Media Player and Windows Media Sharing use this, amongst others.