# NTP via tcp? **URL:** \ **Category:** SLES Networking\ **Created:** [January 11, 2013, 12:36pm UTC](https://forums.suse.com/t/ntp-via-tcp/23496 "2013-01-11T12:36:36Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![System1](https://avatars.discourse-cdn.com/v4/letter/s/51bf81/32.png) [@System1](https://forums.suse.com/u/System1)\ **Post date:** [January 11, 2013, 12:36pm UTC](https://forums.suse.com/t/ntp-via-tcp/23496/1 "2013-01-11T12:36:36Z")
Hi, is there a way to use the TCP-Protocol insteed of the UDP-Protocol for NTP in SLES10/SLES11? (I know that TCP is not smart for NTP but the enviroment use TCP for NTP :-\) Bye Bernd ---
**Author:** ![malcolmlewis](https://sea2.discourse-cdn.com/flex022/user_avatar/forums.suse.com/malcolmlewis/32/11375_2.png) [@malcolmlewis](https://forums.suse.com/u/malcolmlewis)\ **Post date:** [January 11, 2013, 2:29pm UTC](https://forums.suse.com/t/ntp-via-tcp/23496/2 "2013-01-11T14:29:57Z")
> [@](#): > > On Fri 11 Jan 2013 10:36:36 AM CST, Bernd Nachtigall wrote: > > Hi, > > is there a way to use the TCP-Protocol insteed of the UDP-Protocol for > NTP in SLES10/SLES11? (I know that TCP is not smart for NTP but the > enviroment use TCP for NTP :-\) > > Bye > > Bernd Hi You mean the time service on tcp port 37? You would need to enable time and the xinetd service. – Cheers Malcolm °¿° (Linux Counter #276890) openSUSE 12.2 (x86\_64) Kernel 3.4.11-2.16-desktop up 22:41, 3 users, load average: 0.00, 0.03, 0.05 CPU Intel® i5 CPU M520@2.40GHz | GPU Intel® Ironlake Mobile ---
**Author:** ![system](https://us1.discourse-cdn.com/flex022/uploads/suse/original/2X/5/5012ba89e3ffb5220dac47d5ea0ba032e2fe1cb6.png) [@system](https://forums.suse.com/u/system)\ **Post date:** [January 11, 2013, 3:26pm UTC](https://forums.suse.com/t/ntp-via-tcp/23496/3 "2013-01-11T15:26:52Z")
malcolmlewis wrote: [color=blue] > > [@](#): > > > > On Fri 11 Jan 2013 10:36:36 AM CST, Bernd Nachtigall wrote: > > > > Hi, > > > > is there a way to use the TCP-Protocol insteed of the UDP-Protocol for > > NTP in SLES10/SLES11? (I know that TCP is not smart for NTP but the > > enviroment use TCP for NTP :-\) > > > > Bye > > > > Bernd > > Hi > You mean the time service on tcp port 37? You would need to enable time > and the xinetd service. > [/color] No, I mean the Network Time Protocol on Port 123. I assume that timeservice is outdated, isn’t it? Bye Bernd ---
**Author:** ![malcolmlewis](https://sea2.discourse-cdn.com/flex022/user_avatar/forums.suse.com/malcolmlewis/32/11375_2.png) [@malcolmlewis](https://forums.suse.com/u/malcolmlewis)\ **Post date:** [January 11, 2013, 4:25pm UTC](https://forums.suse.com/t/ntp-via-tcp/23496/4 "2013-01-11T16:25:36Z")
> [@](#): > > On Fri 11 Jan 2013 01:26:52 PM CST, Bernd Nachtigall wrote: > > malcolmlewis wrote: > [color=blue] > > > > [@](#): > > > > > > On Fri 11 Jan 2013 10:36:36 AM CST, Bernd Nachtigall wrote: > > > > > > Hi, > > > > > > is there a way to use the TCP-Protocol insteed of the UDP-Protocol for > > > NTP in SLES10/SLES11? (I know that TCP is not smart for NTP but the > > > enviroment use TCP for NTP :-\) > > > > > > Bye > > > > > > Bernd > > > > Hi > > You mean the time service on tcp port 37? You would need to enable > > time and the xinetd service. > > [/color] > > No, > I mean the Network Time Protocol on Port 123. > > I assume that timeservice is outdated, isn’t it? > > Bye > > Bernd Hi The ntp protocol doesn’t/can’t use tcp only udp. So the server you trying to sync to must be either time or daytime? Maybe your time reference system is just using port tcp/123 maybe a packet capture from tcpdump or wireshark might identify. – Cheers Malcolm °¿° (Linux Counter #276890) openSUSE 12.2 (x86\_64) Kernel 3.4.11-2.16-desktop up 1 day 0:18, 3 users, load average: 0.10, 0.10, 0.06 CPU Intel® i5 CPU M520@2.40GHz | GPU Intel® Ironlake Mobile ---
**Author:** ![Jens-U](https://avatars.discourse-cdn.com/v4/letter/j/d78d45/32.png) [@Jens-U](https://forums.suse.com/u/Jens-U)\ **Post date:** [January 15, 2013, 3:52pm UTC](https://forums.suse.com/t/ntp-via-tcp/23496/5 "2013-01-15T15:52:26Z")
[QUOTE=Bernd Nachtigall;11090]Hi, is there a way to use the TCP-Protocol insteed of the UDP-Protocol for NTP in SLES10/SLES11? (I know that TCP is not smart for NTP but the enviroment use TCP for NTP :-\) Bye Bernd[/QUOTE] Hi Bernd, It’d be really interesting to know which “environment” makes use of TCP for NTP, as this violates the RFCs. The latest protocol definition for NTPv4 (RFC 5905) explicitly states in 7.3 that “the NTP packet is a UDP datagram”. Regards, Jens ---
**Author:** ![system](https://us1.discourse-cdn.com/flex022/uploads/suse/original/2X/5/5012ba89e3ffb5220dac47d5ea0ba032e2fe1cb6.png) [@system](https://forums.suse.com/u/system)\ **Post date:** [January 17, 2013, 10:42am UTC](https://forums.suse.com/t/ntp-via-tcp/23496/6 "2013-01-17T10:42:51Z")
jmozdzen wrote: (…)[color=blue] > It’d be really interesting to know which “environment” makes use of TCP > for NTP, as this violates the RFCs. The latest protocol definition for > NTPv4 (RFC 5905) explicitly states in 7.3 that “the NTP packet is a UDP > datagram”.[/color] > (…) There was a firewall which has blocked UDP. But now the service partner who manage this part has corrected the settings. NTP runs fine now 🙂 Thx for the RFC number! Bye Bernd