Following standard industry practice, we make sure each IP address has a corresponding hostname. In October 2009, we started using a single domain name to identify our servers across all Google products, rather than use different product domains such as youtube.com, blogger.com, and google.com. We did this for two reasons: first, to keep things simpler, and second, to proactively improve security by protecting against potential threats such as cross-site scripting attacks.
Most typical Internet users will never see 1e100.net, but we picked a Googley name for it just in case (1e100 is scientific notation for 1 googol).
If you do some further research, you will see that in fact the IP addresses that the domain 1e100.net are owned by Google. Below is an example from the IP referred to above:
Registry WHOIS Server : whois.arin.net
# # Query terms are ambiguous. The query is assumed to be: # “n 184.108.40.206” # # Use “?” to get help. #
# # The following results may also be obtained via: # http://whois.arin.net/rest/nets;q=220.127.116.11?showDetails=true&showARIN=false&ext=netref2 #
NetRange: 18.104.22.168 – 22.214.171.124 CIDR: 126.96.36.199/16 OriginAS: AS15169 NetName: GOOGLE NetHandle: NET-173-194-0-0-1 Parent: NET-173-0-0-0-0 NetType: Direct Allocation RegDate: 2009-08-17 Updated: 2012-02-24 Ref: http://whois.arin.net/rest/net/NET-173-194-0-0-1
OrgName: Google Inc. OrgId: GOGL Address: 1600 Amphitheatre Parkway City: Mountain View StateProv: CA PostalCode: 94043 Country: US RegDate: 2000-03-30 Updated: 2011-09-24 Ref: http://whois.arin.net/rest/org/GOGL
OrgAbuseHandle: ZG39-ARIN OrgAbuseName: Google Inc OrgAbusePhone: +1-650-253-0000 OrgAbuseEmail: arin-contact (at) google.com OrgAbuseRef: http://whois.arin.net/rest/poc/ZG39-ARIN
OrgTechHandle: ZG39-ARIN OrgTechName: Google Inc OrgTechPhone: +1-650-253-0000 OrgTechEmail: arin-contact (at) google.com OrgTechRef: http://whois.arin.net/rest/poc/ZG39-ARIN