Report created on: Mon, 06 Jul 2015 21:25:11 GMT
Parent
100
NS
97
SOA
94
MX
100
Mail
100
Web
100
Parent
NS Records at Parent Servers
We have successfully fetched domain's NS records from parent name server (h.gtld-servers.net.).
Domain NS records:
  • ns1.google.com. TTL=172800 [216.239.32.10] [NO GLUE6]
  • ns2.google.com. TTL=172800 [216.239.34.10] [NO GLUE6]
  • ns3.google.com. TTL=172800 [216.239.36.10] [NO GLUE6]
  • ns4.google.com. TTL=172800 [216.239.38.10] [NO GLUE6]
Missing Glue
OK. Parent name servers are offering glue for domain's name servers. We received name servers list and it's IP addresses from parent name server (h.gtld-servers.net.).
Name Servers Have A Records
OK. Found A records for all name servers.
  • United States ns1.google.com. → 216.239.32.10
  • United States ns2.google.com. → 216.239.34.10
  • United States ns3.google.com. → 216.239.36.10
  • United States ns4.google.com. → 216.239.38.10
To reach your name servers via IPv4 an A record is needed for each name server.
Name Servers Have AAAA Records
NOTICE: While reading domain NS records at parent name servers, we found name servers without AAAA records.
  • ns1.google.com. → ?
  • ns2.google.com. → ?
  • ns3.google.com. → ?
  • ns4.google.com. → ?
To reach your name servers via IPv6 an AAAA record is needed for each name server.
NS
NS Records
Your name servers returned 4 NS records:
  • ns1.google.com. TTL=345600 [216.239.32.10] [NO GLUE6]
  • ns2.google.com. TTL=345600 [216.239.34.10] [NO GLUE6]
  • ns3.google.com. TTL=345600 [216.239.36.10] [NO GLUE6]
  • ns4.google.com. TTL=345600 [216.239.38.10] [NO GLUE6]
All Name Servers Responded
OK. All your name servers responded. We queried domain's records from all of your name servers and we received them successfully.
Glue Check
OK. No differences found. The glue provided by the parent name servers has to match the data provided by the authoritative name servers.
Allow Recursive Queries
OK. Domain name servers are not allowing recursive queries. On all name servers which acts as caching name servers recursive queries should be restricted to local networks. Having open DNS servers can lead to abuses such as cache poisoning and DOS (denial of service) attacks. Cache poisoning attacks allows under certain conditions to redirect legitimate web traffic, email and other traffic to malicious hosts compromising security.
Check Name Servers Count
OK. Domain has 4 name servers. Recommended number, between 2 and 7 name servers (RFC 2182 recommends to have at least 3 authoritative name servers for domains).
Identical NS Records
OK. All your name servers reported identical NS records. Each name server should return identical NS records.
Check for Lame Name servers
OK. No lame name servers found. All of your name servers are configured to be either master or slave for your domain.
Check All IPs are Public
OK. No private IPs found. Name servers using private IPs can't be reached from the Internet causing DNS delays.
Name Servers Have A Records
OK. Found A records for each name servers.
  • United States ns1.google.com. → 216.239.32.10
  • United States ns2.google.com. → 216.239.34.10
  • United States ns3.google.com. → 216.239.36.10
  • United States ns4.google.com. → 216.239.38.10
To reach your name servers via IPv4 an A record is needed for each name server.
Name Servers Have AAAA Records
NOTICE: We found name servers without AAAA records.
  • ns1.google.com. → ?
  • ns2.google.com. → ?
  • ns3.google.com. → ?
  • ns4.google.com. → ?
To reach your name servers via IPv6 an AAAA record is needed for each name server.
Name Servers Have Valid Names
OK. All names are valid. Name server name should be a valid host name, no partial name or IP address.
Check for Stealth Name Servers
OK. No stealth name servers found. All name servers returned by domain name servers should be listed at parent servers.
Check for Missing Name Servers
OK. No missing name servers found. All name servers returned by the parent name servers should have an NS record at your name servers.
No CNAME in NS Records
OK. No CNAMEs found in NS records. RFC 2181, section 10.3 says that host name must map directly to one or more address record (A or AAAA) and must not point to any CNAME records. RFC 1034, section 3.6.2 says if a name appears in the right-hand side of RR (Resource Record) it should not appear in the left-hand name of CNAME RR, thus CNAME records should not be used with NS and MX records. Despite this restrictions, there are many working configuration using CNAME with NS and MX records.
Allow TCP connections
OK. All name servers are allowing TCP connections. When response to a DNS query exceeds 512 bytes, TCP is negotiated and used, all name servers should allow TCP connections (port 53).
Name Servers Distributed on Multiple Networks
OK. Name servers are dispersed on 4 different C class networks:
  • 216.239.32.0/24:
    • ns1.google.com.
  • 216.239.34.0/24:
    • ns2.google.com.
  • 216.239.36.0/24:
    • ns3.google.com.
  • 216.239.38.0/24:
    • ns4.google.com.
Name servers should be dispersed (topologically and geographically) across the Internet to avoid risk of single point of failure (RFC 2182).
Name Servers Distributed on Multiple ASNs
WARNING: All name servers are located in one Autonomous System:
  • AS15169:
    • ns1.google.com.
    • ns2.google.com.
    • ns3.google.com.
    • ns4.google.com.
Name servers should be dispersed (topologically and geographically) across the Internet to avoid risk of single point of failure (RFC 2182).
Name Servers Versions
OK. Name servers software versions are not exposed:
  • 216.239.32.10: "unknown"
  • 216.239.34.10: "unknown"
  • 216.239.36.10: "unknown"
  • 216.239.38.10: "unknown"
Exposing name server's versions may be risky, when a new vulnerability is found your name servers may be automatically exploited by script kiddies until you patch the system. Learn how to hide version.
SOA
Check SOA Record
Domain SOA Record:
  • Primary nameserver: ns1.google.com.
  • Hostmaster (e-mail): dns-admin.google.com.
  • Serial: 4294967295
  • Refresh: 7200
  • Retry: 1800
  • Expire: 1209600
  • Minimum TTL: 300
Name Servers Agreement on Serial Number
OK. All name servers (4) have the same serial number [4294967295]. Having different serials on your name servers may show inconsistencies between name servers configuration (multiple masters), or communication errors (ACL and firewall issues).
SOA Number Format
NOTICE: Alhough your serial is valid [4294967295], it's not using recommended serial number format YYYYMMDDnn, where YYYY is four-digit year number, MM is the month, DD is the day and nn is the sequence number in case zone file is updated more than once per day.
SOA Mname
OK. Primary name server is ns1.google.com. and is listed at the parent name servers. The MNAME field defines the Primary Master name server for the zone, this name server should be found in your NS records.
SOA Rname
OK. Contact email for DNS problems is dns-admin@google.com. (dns-admin.google.com.). RNAME field defines an administrative email for your zone. RFC2142 recommends using hostmaster e-mail for this purpose, but any valid e-mail address can be used.
SOA Refresh
OK. Refresh interval is 7200. Recommended values [1200 .. 43200] (20 min ... 12 hours). Refresh field from SOA record determines how quickly zone changes are propagated from master to slave.
SOA Retry
OK. Retry interval is 1800. Recommended values [120 .. 7200] (2 minutes .. 2 hours). Retry field from SOA record defines how often slave should retry contacting master if connection to master failed during refresh.
SOA Expire
OK. Expire interval is 1209600. Recommended values [604800 .. 1209600] (1 week ... 2 weeks). Expiry defines zone expiration time in seconds after which slave must re-validate zone file, if contacting master fails then slave will stop responding to any queries.
SOA Minimum TTL
WARNING: Minimum TTL value is 300. Recommended values [3600 .. 86400] (1 hour ... 1 day). Minimum TTL was redefined in RFC 2308, now it defines the period of time used by slaves to cache negative responses.
MX
MX Records
Your name servers returned 5 MX records:
  • 10 aspmx.l.google.com. TTL=600
  • 20 alt1.aspmx.l.google.com. TTL=600
  • 30 alt2.aspmx.l.google.com. TTL=600
  • 40 alt3.aspmx.l.google.com. TTL=600
  • 50 alt4.aspmx.l.google.com. TTL=600
Identical MX Records
OK. All name servers returned identical MX records.
Mail Servers Have A Records
OK. Found A records for all mail servers.
  • United States alt1.aspmx.l.google.com. → 74.125.143.27
  • United States alt2.aspmx.l.google.com. → 74.125.68.27
  • United States alt3.aspmx.l.google.com. → 64.233.189.27
  • United States alt4.aspmx.l.google.com. → 173.194.72.27
  • United States aspmx.l.google.com. → 173.194.67.27
To reach your mail servers via IPv4 an A record is needed for each mail server.
Mail Servers Have AAAA Records
OK. Found AAAA records for all mail servers.
  • alt1.aspmx.l.google.com. → 2a00:1450:4010:c03::1b
  • alt2.aspmx.l.google.com. → 2404:6800:4003:c02::1b
  • alt3.aspmx.l.google.com. → 2404:6800:4008:c07::1b
  • alt4.aspmx.l.google.com. → 2404:6800:4008:c01::1b
  • aspmx.l.google.com. → 2a00:1450:400c:c05::1a
To reach your mail servers via IPv6 an AAAA record is needed for each mail server.
Reverse Entries for MX records
OK. All mail servers have reverse DNS entries configured correctly.
Server IP PTR (Reverse) IPs
aspmx.l.google.com. 173.194.67.27 wi-in-f27.1e100.net. 74.125.0.27, 173.194.67.27, 216.239.32.27
alt1.aspmx.l.google.com. 74.125.143.27 la-in-f27.1e100.net. 74.125.0.27, 216.239.32.27, 74.125.143.27
alt2.aspmx.l.google.com. 74.125.68.27 sc-in-f27.1e100.net. 216.239.32.27, 74.125.0.27, 74.125.68.27
alt3.aspmx.l.google.com. 64.233.189.27 tl-in-f27.1e100.net. 216.239.32.27, 74.125.0.27, 64.233.189.27
alt4.aspmx.l.google.com. 173.194.72.27 tf-in-f27.1e100.net. 216.239.32.27, 74.125.0.27, 173.194.72.27
aspmx.l.google.com. 2a00:1450:400c:c05::1a wi-in-x1a.1e100.net. 2a00:1450:400c:c05::1a
alt1.aspmx.l.google.com. 2a00:1450:4010:c03::1b la-in-x1b.1e100.net. 2a00:1450:4010:c03::1b
alt2.aspmx.l.google.com. 2404:6800:4003:c02::1b sc-in-x1b.1e100.net. 2404:6800:4003:c02::1b
alt3.aspmx.l.google.com. 2404:6800:4008:c07::1b tl-in-x1b.1e100.net. 2404:6800:4008:c07::1b
alt4.aspmx.l.google.com. 2404:6800:4008:c01::1b tf-in-x1b.1e100.net. 2404:6800:4008:c01::1b

All mail servers should have a reverse DNS (PTR) entry for each IP address (RFC 1912). Missing reverse DNS entries will make many mail servers to reject your e-mails or mark them as SPAM.

All IP's reverse DNS entries should resolve back to IP address (IP → PTR → IP). Many mail servers are configured to reject e-mails from IPs with inconsistent reverse DNS configuration.

Check MX Records for Invalid Chars
OK. No invalid characters found. Name field from MX records should be a valid host name.
Check MX Records IPs are Public
OK. No private IPs found. Mail servers using private IPs can't be reached from the Internet causing mail delivery delays.
Check MX Records for Duplicates
OK. No MX records duplicates (same IP addresses) found. Although technically valid, duplicate MX records have no benefits and can cause confusion.
Only Host Names in MX Records
OK. No IPs found in MX records. IP addresses are not allowed in MX records, only host names.
No CNAME in MX Records
OK. No CNAMEs found in MX records. RFC 2181, section 10.3 says that host name must map directly to one or more address record (A or AAAA) and must not point to any CNAME records. RFC 1034, section 3.6.2 says if a name appears in the right-hand side of RR (Resource Record) it should not appear in the left-hand name of CNAME RR, thus CNAME records should not be used with NS and MX records. Despite this restrictions, there are many working configuration using CNAME with NS and MX records.
RBL Check
OK. Mail servers IPs are not blacklisted.
Check Google Apps Settings
OK. Domain is using Google Apps and it's configured correctly.

Google Apps Support: Configuring Your MX Records

Mail
Connect to Mail Servers
OK. Successfully connected to all mail servers.
  • alt1.aspmx.l.google.com.:
    220 mx.google.com ESMTP f6si16275649lam.85 - gsmtp
  • alt2.aspmx.l.google.com.:
    220 mx.google.com ESMTP bf7si30886408pdb.153 - gsmtp
  • alt3.aspmx.l.google.com.:
    220 mx.google.com ESMTP l1si30774585pbq.231 - gsmtp
  • alt4.aspmx.l.google.com.:
    220 mx.google.com ESMTP hy8si30857014pab.227 - gsmtp
  • aspmx.l.google.com.:
    220 mx.google.com ESMTP fx1si21511928wic.87 - gsmtp
To receive emails, mail servers should allow TCP connections on port 25.
Mail Greeting
NOTICE: I've found differences between mail server host names and greeting host name. The following mail servers claims to be other hosts (reverse DNS checks may be wrong):
  • alt1.aspmx.l.google.com.mx.google.com
  • alt2.aspmx.l.google.com.mx.google.com
  • alt3.aspmx.l.google.com.mx.google.com
  • alt4.aspmx.l.google.com.mx.google.com
  • aspmx.l.google.com.mx.google.com
Accepts Postmaster Address
OK. All mail servers are accepting emails to postmaster@google.com address:
  • alt1.aspmx.l.google.com.
    >> MAIL FROM: <dnsreport@dnsinspect.com>
    << 250 2.1.0 OK f6si16275649lam.85 - gsmtp
    >> RCPT TO: <postmaster@google.com>
    << 250 2.1.5 OK f6si16275649lam.85 - gsmtp
    
  • alt2.aspmx.l.google.com.
    >> MAIL FROM: <dnsreport@dnsinspect.com>
    << 250 2.1.0 OK bf7si30886408pdb.153 - gsmtp
    >> RCPT TO: <postmaster@google.com>
    << 250 2.1.5 OK bf7si30886408pdb.153 - gsmtp
    
  • alt3.aspmx.l.google.com.
    >> MAIL FROM: <dnsreport@dnsinspect.com>
    << 250 2.1.0 OK l1si30774585pbq.231 - gsmtp
    >> RCPT TO: <postmaster@google.com>
    << 250 2.1.5 OK l1si30774585pbq.231 - gsmtp
    
  • alt4.aspmx.l.google.com.
    >> MAIL FROM: <dnsreport@dnsinspect.com>
    << 250 2.1.0 OK hy8si30857014pab.227 - gsmtp
    >> RCPT TO: <postmaster@google.com>
    << 250 2.1.5 OK hy8si30857014pab.227 - gsmtp
    
  • aspmx.l.google.com.
    >> MAIL FROM: <dnsreport@dnsinspect.com>
    << 250 2.1.0 OK fx1si21511928wic.87 - gsmtp
    >> RCPT TO: <postmaster@google.com>
    << 250 2.1.5 OK fx1si21511928wic.87 - gsmtp
    
RFC 822, RFC 1123 and RFC 2821 requires that all domain's mail servers should accept e-mails to postmaster. To be compliant you can create an alias and forward all postmaster's e-mails to a valid mailbox.
Accepts Abuse Address
OK. All mail servers are accepting emails to abuse@google.com address:
  • alt1.aspmx.l.google.com.
    >> MAIL FROM: <dnsreport@dnsinspect.com>
    << 250 2.1.0 OK f6si16275649lam.85 - gsmtp
    >> RCPT TO: <abuse@google.com>
    << 250 2.1.5 OK f6si16275649lam.85 - gsmtp
    
  • alt2.aspmx.l.google.com.
    >> MAIL FROM: <dnsreport@dnsinspect.com>
    << 250 2.1.0 OK bf7si30886408pdb.153 - gsmtp
    >> RCPT TO: <abuse@google.com>
    << 250 2.1.5 OK bf7si30886408pdb.153 - gsmtp
    
  • alt3.aspmx.l.google.com.
    >> MAIL FROM: <dnsreport@dnsinspect.com>
    << 250 2.1.0 OK l1si30774585pbq.231 - gsmtp
    >> RCPT TO: <abuse@google.com>
    << 250 2.1.5 OK l1si30774585pbq.231 - gsmtp
    
  • alt4.aspmx.l.google.com.
    >> MAIL FROM: <dnsreport@dnsinspect.com>
    << 250 2.1.0 OK hy8si30857014pab.227 - gsmtp
    >> RCPT TO: <abuse@google.com>
    << 250 2.1.5 OK hy8si30857014pab.227 - gsmtp
    
  • aspmx.l.google.com.
    >> MAIL FROM: <dnsreport@dnsinspect.com>
    << 250 2.1.0 OK fx1si21511928wic.87 - gsmtp
    >> RCPT TO: <abuse@google.com>
    << 250 2.1.5 OK fx1si21511928wic.87 - gsmtp
    
Check SPF record
OK. Found SPF record:
  • v=spf1 include:_spf.google.com ~all
SPF (Sender Policy Framework) record is designed to prevent e-mail SPAM. Typical SPF record would be:
v=spf1 a mx ~all or v=spf1 a mx include:_spf.google.com ~all if you are using Google Apps.
Identical TXT records
OK. Name servers returned identical TXT records. Only SPF records are compared, all name servers should return identical SPF records.
Check DMARC record
OK. Found DMARC record:
  • v=DMARC1; p=quarantine; rua=mailto:mailauth-reports@google.com
DMARC (Domain-based Message Authentication, Reporting & Conformance) helps reducing potential of email-based abuse such as spam and phishing e-mails.
Web
Resolve Domain Name
OK. Domain google.com. resolves to:
  • United States 216.58.210.78
Domain Name IPs are Public
OK. No private IPs found for google.com.. Web servers using private IPs can't be reached from the Internet.
Resolve WWW
OK. Domain www.google.com. resolves to:
  • United States 74.125.206.105
  • United States 74.125.206.99
  • United States 74.125.206.147
  • United States 74.125.206.106
  • United States 74.125.206.103
  • United States 74.125.206.104
WWW IPs are Public
OK. No private IPs found for www.google.com.. Web servers using private IPs can't be reached from the Internet.

Report completed in 5.89 seconds.

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