NTP users are strongly urged to take immediate action to ensure that their NTP daemons are not susceptible to use in a distributed denial-of-service (DDoS) attack. Please also take this opportunity to defeat denial-of-service attacks by implementing ingress and Egress filtering through BCP38.
ntp-4.2.8p2, released on 7 April 2015, addresses two issues with crafted packets involving symmetric key encryption and Message Authentication Codes.
Are you using Autokey in production? If so, please contact Harlan - he's got some questions for you.
Welcome to the NTP.Servers Web.
This web-based collaboration area provides lists of Network Time Protocol (NTP) public time servers. NTP users looking for information about installing, configuring, etc. NTP should visit the NTP Support
Please read the Rules Of Engagement before using these lists. These lists are updated frequently and should not be cached.
About the Public NTP Time Server Lists
The lists are provided for information purposes only and represent the best information available at the current date. The operators of the servers listed do not commit to provide time service other than on a volunteer basis and with no guarantee of accuracy or availability. Further information of a technical nature can be obtained from the www.ntp.org
site, the comp.protocols.time.ntp
newsgroup, or the NTP Support
The list of primary (stratum 1
) and secondary (stratum 2
) designates the NTP time servers available for public access under stated restrictions. Each entry gives the country code, state (US only), host name, Internet address, approximate location and geographic coordinates (if available), synchronization source (stratum, type of radio or satellite receiver and host type), suggested service area, access policy (as notified) and responsible person name and e-mail address. Most servers indicate the NTP version as well. It is always wise to consult the DNS to verify host addresses, which are changed from time to time. When more than one address is given, preference should given to each in order.
Please respect the access policy as stated by the responsible person. It is very important that potential clients avoid use of servers not listed as open access, unless approved first by the responsible person. This especially includes indiscriminate use of servers not listed in the list, since this can be disruptive. The responsible person should always be notified upon establishment of regular operations with servers listed as open access. Servers listed as closed access should NOT be used without prior permission, since this may disrupt ongoing activities in which these servers are involved.
All primary and secondary servers listed have no access restrictions, so that service is available for any client with a valid IP address. Where noted, some servers enforce a limit on the number of clients from any one network other than the server network itself. Where noted, some servers provide a cryptographic authentication service. Contact the site operators for further details.
Finding A Time Server
Browsing the Lists
lists are available from the following links. For detailed information about a server click the hostname in the list.
Searching for A Time Server
to search the Time Server Lists based on various criteria.
You may also search for your List entry by entering a portion of your host name (e.g. the domain) as lower case
text in the Go/Search
box at the top of any page and clicking the Go/Search
button. If there is only one match you will see that Time Server List entry. If there are multiple matches you will see a page with clickable links to the matching entries.
Adding your Server to the Lists
Time Server operators may add, and maintain, their own List entries after they register
at the NTP Public Service Project web-site. This is the recommended means of managing your List entries.
Please read ManagingYourListEntries
for more information.
Time Server operators may choose to submit their List entries via e-mail to firstname.lastname@example.org.
List entries submitted in this fashion will be entered by a volunteer when time permits. Please read SubmittingYourListEntriesViaEmail
for more information.
Removing your Server from the Lists
Time Server operators who wish to remove their servers from the list may to so by editing their List entries and changing the ServerStratum
Time Server operators must be registered
at the NTP Public Services Project web-site and must be on their List entry ACL to be able to edit their entries.
Time Server operators may choose submit a removal request via e-mail to email@example.com.
Removal requests submitted in this fashion will be processed by a volunteer when time permits.
Reporting Broken Time Servers
Anyone discovering TimeServers
that are broken (e.g. non-functional, incorrect stratum, etc.) for an extended period of time should contact firstname.lastname@example.org
only after attempting to contact the server operator.
Problems with the NTP Pool
must be reported to the NTP Pool Manager
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