What are googleads.g.doubleclick.net and tpc.googlesyndication.com?
2018-07-01 ONE NET WIKI
Are you receiving refferal traffic from googleads.g.doubleclick.net and tpc.googlesyndication.com?
They are not viruses.
Referrals from googleads.g.doubleclick.net are clicks on your ads showing on the Google Display Network—specifically, ads showing on publisher sites in the AdSense program—for which the destination URLs have not been tagged.
If you notice googleads.g.doubleclick.net appearing in your reports, check to see if auto-tagging is turned on in your AdWords account, and that your own campaign variables are labeled correctly.
Similarly, referrals from tpc.googlesyndication.com are clicks on ads showing on the DoubleClick network.
googlesyndication.com is a domain owned by Google that is used for storing and loading ad content and other resources relating to ads for Google AdSense and DoubleClick from the Google CDN.