If you are using a static IP (and not just a DHCP reservation) make sure that no other client in your network uses the same ip address. Based on the frequency of incidents you've mentioned, it really sounds like conflicting ips.
If you are using a static IP (and not just a DHCP reservation) make sure that no other client in your network uses the same ip address. Based on the frequency of incidents you've mentioned, it really sounds like conflicting ips.