Report for htw.uni-sb.de
NS Records at Parent Servers
We have successfully fetched domain's NS records from parent name server (
ns1.rz.uni-sb.de.).
Domain NS records:
-
ns.rz.uni-saarland.de. TTL=86400
[NO GLUE4]
[NO GLUE6]
-
ns1.rz.uni-saarland.de. TTL=86400
[NO GLUE4]
[NO GLUE6]
Test ignored, name servers are located outside of current zone.
Name Servers Have A Records
OK.
Found A records for all name servers.
- ns.rz.uni-saarland.de. → 134.96.7.7
- ns1.rz.uni-saarland.de. → 134.96.100.105
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.
- ns.rz.uni-saarland.de. → ?
- ns1.rz.uni-saarland.de. → 2001:638:200:811b:0:1:0:1
To reach your name servers via IPv6 an AAAA record is needed for each name server.
Your name servers returned
2 NS records:
-
ns.rz.uni-saarland.de. TTL=86400
[NO GLUE4]
[NO GLUE6]
-
ns1.rz.uni-saarland.de. TTL=86400
[NO GLUE4]
[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.
OK.
No differences found.
The glue provided by the parent name servers has to match
the data provided by the authoritative name servers.
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.
OK.
Domain has 2 name servers. Recommended number,
between 2 and 7 name servers (RFC 2182 recommends to have at
least 3 authoritative name servers for domains).
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.
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.
- ns.rz.uni-saarland.de. → 134.96.7.7
- ns1.rz.uni-saarland.de. → 134.96.100.105
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.
- ns.rz.uni-saarland.de. → ?
- ns1.rz.uni-saarland.de. → 2001:638:200:811b:0:1:0:1
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.
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.
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 2
different C class networks:
-
134.96.100.0/24:
-
134.96.7.0/24:
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:
-
AS680:
- ns.rz.uni-saarland.de.
- ns1.rz.uni-saarland.de.
Name servers should be dispersed (topologically and geographically)
across the Internet to avoid risk of single point of failure (RFC 2182).
OK.
Name servers software versions are not exposed:
- 134.96.100.105: "unknown"
- 134.96.7.7: "0"
- 2001:638:200:811b:0:1:0:1: "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.
Domain SOA Record:
- Primary nameserver: ns.rz.uni-saarland.de.
- Hostmaster (e-mail): hostmaster.uni-saarland.de.
- Serial: 2024041100
- Refresh: 14400
- Retry: 3600
- Expire: 1209600
- Minimum TTL: 3600
Name Servers Agreement on Serial Number
OK.
All name servers (2) have the same
serial number [2024041100].
Having different serials on your name servers may show inconsistencies between name servers
configuration (multiple masters), or communication errors (ACL and firewall issues).
OK.
Serial number format OK [2024041100].
Your serial number is following general convention for
serial number 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.
OK.
Primary name server is ns.rz.uni-saarland.de. 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.
OK.
Contact email for DNS problems is
[email protected]. (
hostmaster.uni-saarland.de.).
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.
OK.
Refresh interval is 14400.
Recommended values [1200 .. 43200] (20 min ... 12 hours).
Refresh field from SOA record determines how quickly zone changes are propagated from master to slave.
OK.
Retry interval is 3600.
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.
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.
OK.
Minimum TTL value is 3600.
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.
Your name servers returned
1 MX records:
-
20 m-relay2.rz.uni-saarland.de. TTL=86400
OK.
All name servers returned identical MX records.
Mail Servers Have A Records
OK.
Found A records for all mail servers.
- m-relay2.rz.uni-saarland.de. → 134.96.7.8
To reach your mail servers via IPv4 an A record is needed for each mail server.
Mail Servers Have AAAA Records
NOTICE:
While reading domain NS records at parent mail servers,
we found mail servers without AAAA records.
- m-relay2.rz.uni-saarland.de. → ?
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 |
|
m-relay2.rz.uni-saarland.de. |
134.96.7.8 |
eris.rz.uni-saarland.de. |
134.96.7.8 |
|
m-relay2.rz.uni-saarland.de. |
134.96.7.8 |
m-relay2.rz.uni-saarland.de. |
134.96.7.8 |
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.
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.
OK.
Mail servers IPs are not blacklisted.
Check Google Apps Settings
Test ignored, domain is not using Google Apps.
FAIL:
Connection to all mail servers failed.
- m-relay2.rz.uni-saarland.de.:
Server checks disabled due complaints.
To receive emails, mail servers should allow TCP connections on port 25.
OK.
No differences between mail server host names and greeting host name.
Accepts Postmaster Address
Temporary error, could not determine if
all mail servers are accepting emails to
[email protected] address:
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.
Temporary error, could not determine if
all mail servers are accepting emails to
[email protected] address:
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.
OK.
Found SPF record:
- v=spf1 a mx ip4:134.96.7.0/24 ip4:134.96.40.64/28 ip6:2001:638:200:853F:0:1::/112 ~all
SPF
(Sender Policy Framework) record is designed to prevent e-mail spoofing.
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.
OK.
Name servers returned identical TXT records.
Only SPF records are compared, all name servers should return identical SPF records.
No SPF type records found.
All name servers should return identical SPF records.
NOTICE:
Domain doesn't have DMARC record.
DMARC
(Domain-based Message Authentication, Reporting & Conformance)
helps reducing potential of email-based abuse such as spam and
phishing e-mails.
WARNING:
Could not resolve domain htw.uni-sb.de..
Domain Name IPs are Public
Could not resolve htw.uni-sb.de..
WARNING:
Could not resolve domain www.htw.uni-sb.de..
Could not resolve www.htw.uni-sb.de..
Report completed in 1.28 seconds.
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