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Author Topic: SNTP  (Read 1099 times)

burakkucat

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SNTP
« on: April 01, 2020, 01:21:05 AM »

Late-ish yesterday evening (March 31, 2020) I was asked to comment on the following --

|                 | Ntfcn |                                                         |                     |
| Entity          | Code  | Description                                             | Date/Time           |
|-----------------|-------|---------------------------------------------------------|---------------------|
| system          | Minor | SNTP server not found                                   | 2020-03-31,21:37:41 |

There wasn't much I could say . . .  ::) 

But I asked how the device was configured. In return I was shown --

:--> sntpclient <tab>
mode                             Set SNTP client mode
server                           Configure the system to use the simple network
                                 timing protocol (SNTP) to request and accept
                                 Network Timing Protocol traffic from a time
                                 server

:--> sntpclient server <tab>
<address>                        IP Address (e.g. 10.10.1.1)

:--> sntpclient mode <tab>
anycast                          Enable simple network timing protocol (SNTP)
                                 anycast mode. This mode will use broadcast
                                 packets to locate the SNTP server. On response
                                 from the first server it will establish a link
                                 for future operations in unicast mode.
disable                          Disable simple network timing protocol (SNTP)
                                 mode.
unicast                          Enable simple network timing protocol (SNTP)
                                 unicast mode. The system will use a
                                 specified unicast IP address to sync the
                                 client to the server.

:-->

That example shows an RFC1918 address for the time server. I guess that was used for convenience and a routeable address would also be viable. (I have very little experience with configuring (S)NTP clients, other than pointing simple devices to [0-3].uk.pool.ntp.org)

Continuing to "pull teeth", I asked what was the actual configuration that the device was currently using. The response was --

:--> show sntpclient

SNTP Client Information:
                           Mode: Unicast
                  Active Server: 0.0.0.0

 Available Unicast SNTP Servers:
 | Server Address   | Active | Type    |
 |------------------|--------|---------|
 | 204.2.134.162    | false  | static  |

:-->

Unicast mode, o.k., I think.
Explicit IPv4 address, hmm . . . I wonder who/where?

A reverse DNS look-up shows --

Code: [Select]
[bcat ~]$ host 204.2.134.162
162.134.2.204.in-addr.arpa domain name pointer paladin.latt.net.
[bcat ~]$

Which means nothing, to me.

Pointing a web-browser at "latt.net" results in a clear, white, page, with one centred line that reads --

Quote
THIS PAGE INTENTIONALLY LEFT BLANK.

So how about a "whois"?

Code: [Select]
[bcat ~]$ whois 204.2.134.162
[Querying whois.arin.net]
[Redirected to rwhois.gin.ntt.net:4321]
[Querying rwhois.gin.ntt.net]
[rwhois.gin.ntt.net]
%rwhois V-1.5:0078b6:00 rwhois.gin.ntt.net (Vipar 0.1a. Comments to vipar@us.ntt.net)
network:Class-Name:network
network:Auth-Area:204.2.128.0/20
network:ID:BBBA-204-2-134-0.127.0.0.1/32
network:Handle:BBBA-204-2-134-0
network:Network-Name:BBBA-204-2-134-0
network:IP-Network:204.2.134.0/24
network:In-Addr-Server;I:PDTI1-HST.127.0.0.1/32
network:In-Addr-Server;I:PDTI2-HST.127.0.0.1/32
network:In-Addr-Server;I:PDTI3-HST.127.0.0.1/32
network:In-Addr-Server;I:PDTI4-HST.127.0.0.1/32
network:IP-Network-Block:204.2.134.0 - 204.2.134.255
network:Org-Name:Pacific Data & Telephony
network:Street-Address:11 Great Oaks Blvd, 1st Fir-Cage
network:City:San Jose
network:State:CA
network:Postal-Code:95119
network:Country-Code:US
network:Tech-Contact;I:PDTI-NTTA.127.0.0.1/32
network:Created:2012-06-05 14:44:47.128037+00
network:Updated:2019-02-26 15:56:47.78261+00

network:Class-Name:network
network:Auth-Area:204.2.128.0/20
network:ID:NETBLK-USV4-204-2-128.127.0.0.1/32
network:Handle:NETBLK-USV4-204-2-128
network:Network-Name:USV4-204-2-128
network:IP-Network:204.2.128.0/20
network:In-Addr-Server;I:GIN1-HST.127.0.0.1/32
network:In-Addr-Server;I:GIN2-HST.127.0.0.1/32
network:In-Addr-Server;I:GIN3-HST.127.0.0.1/32
network:In-Addr-Server;I:GIN4-HST.127.0.0.1/32
network:In-Addr-Server;I:GIN5-HST.127.0.0.1/32
network:IP-Network-Block:204.2.128.0 - 204.2.143.255
network:Org-Name:NTT America
network:Street-Address:8300 E Maplewood Ave. Suite 400
network:City:Greenwood Village
network:State:CO
network:Postal-Code:80111
network:Country-Code:US
network:Tech-Contact;I:GIN-BBV4.127.0.0.1/32
network:Created:2005-06-08 19:40:00+00
network:Updated:2019-02-26 15:56:39.42529+00

network:Class-Name:network
network:Auth-Area:204.2.128.0/20
network:ID:NETBLK-VRIOBB-204-002-128.127.0.0.1/32
network:Handle:NETBLK-VRIOBB-204-002-128
network:Network-Name:VRIOBB-204-002-128
network:IP-Network:204.2.128.0/17
network:In-Addr-Server;I:GIN1-HST.127.0.0.1/32
network:In-Addr-Server;I:GIN2-HST.127.0.0.1/32
network:In-Addr-Server;I:GIN3-HST.127.0.0.1/32
network:In-Addr-Server;I:GIN4-HST.127.0.0.1/32
network:In-Addr-Server;I:GIN5-HST.127.0.0.1/32
network:IP-Network-Block:204.2.128.0 - 204.2.255.255
network:Org-Name:NTT America, Inc.
network:Street-Address:8300 E Maplewood Ave. Suite 400
network:City:Greenwood Village
network:State:CO
network:Postal-Code:80111
network:Country-Code:US
network:Tech-Contact;I:VIA4-ORG-ARIN.127.0.0.1/32
network:Created:2001-02-16 05:27:11+00
network:Updated:2008-03-01 00:34:17+00

network:Class-Name:network
network:Auth-Area:204.2.128.0/20
network:ID:NETBLK-VRIO-204-000.127.0.0.1/32
network:Handle:NETBLK-VRIO-204-000
network:Network-Name:VRIO-204-000
network:IP-Network:204.0.0.0/14
network:In-Addr-Server;I:AUTH21-GIN-HST.127.0.0.1/32
network:In-Addr-Server;I:AUTH22-GIN-HST.127.0.0.1/32
network:In-Addr-Server;I:AUTH23-GIN-HST.127.0.0.1/32
network:In-Addr-Server;I:AUTH24-GIN-HST.127.0.0.1/32
network:In-Addr-Server;I:AUTH25-GIN-HST.127.0.0.1/32
network:IP-Network-Block:204.0.0.0 - 204.3.255.255
network:Org-Name:NTT America, Inc.
network:Street-Address:8300 E Maplewood Ave. Suite 400
network:City:Greenwood Village
network:State:CO
network:Postal-Code:80111
network:Country-Code:US
network:Tech-Contact;I:VIA4-ORG-ARIN.127.0.0.1/32
network:Created:2000-07-16 17:02:46+00
network:Updated:2007-07-18 23:10:07+00

network:Class-Name:network
network:Auth-Area:204.2.128.0/20
network:ID:NETBLK-USV4-204-2-128.127.0.0.1/32
network:Handle:NETBLK-USV4-204-2-128
network:Network-Name:USV4-204-2-128
network:IP-Network:204.2.128.0/20
network:In-Addr-Server;I:GIN1-HST.127.0.0.1/32
network:In-Addr-Server;I:GIN2-HST.127.0.0.1/32
network:In-Addr-Server;I:GIN3-HST.127.0.0.1/32
network:In-Addr-Server;I:GIN4-HST.127.0.0.1/32
network:In-Addr-Server;I:GIN5-HST.127.0.0.1/32
network:IP-Network-Block:204.2.128.0 - 204.2.143.255
network:Org-Name:NTT America
network:Street-Address:8300 E Maplewood Ave. Suite 400
network:City:Greenwood Village
network:State:CO
network:Postal-Code:80111
network:Country-Code:US
network:Tech-Contact;I:GIN-BBV4.127.0.0.1/32
network:Created:2005-06-08 19:40:00+00
network:Updated:2019-02-26 15:56:39.42529+00

%ok
[bcat ~]$

I guess that address points to a time-server in the USA. As for its status . . .  :shrug2:

Finally, my query about the device configuration. The device, an SNTP client, is set to unicast mode. Is that sensible? I think so - as long as it is pointed to a viable NTP server, which is addressed by its IPv4 address.
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burakkucat

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Re: SNTP
« Reply #1 on: April 01, 2020, 01:28:36 AM »

For fun, I decided to take a look at what IPv4 addresses the [0-3].uk.pool.ntp.org time servers currently returned --

Code: [Select]
[bcat ~]$ for H in 0 1 2 3; do host $H.uk.pool.ntp.org; done | awk '$3 !~ /IPv6/ { print $4 }' | sort -g | uniq
46.227.200.72
51.89.151.183
81.21.65.169
85.199.214.100
85.199.214.101
85.199.214.98
162.159.200.1
162.159.200.123
176.58.109.199
178.62.250.107
185.121.25.166
185.121.25.242
185.83.169.27
193.150.34.2
212.71.248.69
[bcat ~]$

Perhaps I should suggest that the above device should be configured to use one of those addresses instead of 204.2.134.162 . . .
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DaveC

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Re: SNTP
« Reply #2 on: April 01, 2020, 04:12:42 PM »

If you google the IP address, the first hit is a page on www.pool.ntp.org:

https://www.pool.ntp.org/scores/204.2.134.162

So it looks like a valid server in pool.ntp.org.  "ntpdate -q 204.2.134.162" seems to show it is currently alive and responsive.

Does the line " Available Unicast SNTP Servers:" mean it can be configured with multiple IP addresses ?  That might be a better solution if it doesn't accept a domain name.
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burakkucat

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Re: SNTP
« Reply #3 on: April 01, 2020, 10:30:58 PM »

If you google the IP address, the first hit is a page on www.pool.ntp.org:

https://www.pool.ntp.org/scores/204.2.134.162

So it looks like a valid server in pool.ntp.org.  "ntpdate -q 204.2.134.162" seems to show it is currently alive and responsive.

Thanks for performing the test. I had forgotten about ntpdate, for it has been marked as deprecated for quite some time.

Quote
Does the line " Available Unicast SNTP Servers:" mean it can be configured with multiple IP addresses ?  That might be a better solution if it doesn't accept a domain name.

Well spotted. I hadn't noticed the plurality. I'll make the suggestion that as many as possible IPv4 addresses should be specified from the [0-3].uk.pool.ntp.org list.
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Weaver

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Re: SNTP
« Reply #4 on: April 01, 2020, 11:10:01 PM »

I have used my ISP’s server as the first in lists, because it’s low latency. In turn, my Firebrick is an NTP server too so everything on the LAN refers only to that now. I made up a domain name something like ntp.weaver.org = firebrick.weaver.org and in turn ntp‑external.weaver.org = time.aa.net.uk ; or something, can’t remember what, for my own domain names. And everything was already set to refer to ntp.weaver.org so I could move/change the server by just changing the rhs of a CNAME.
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burakkucat

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Re: SNTP
« Reply #5 on: April 01, 2020, 11:38:45 PM »

<Nods> I seem to have a vague memory of you setting it up. A perfectly logical configuration.
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Weaver

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Re: SNTP
« Reply #6 on: April 02, 2020, 12:19:37 AM »

I can set up arbitrary domain name definitions using AA’s clueless.aa.net.uk server. I have dozens and dozens of them. Including one for every box in my network. A lot of cnames too, for convenience, where I can’t remember which one of several possible domain names it is that I have to use, so that anything works; all possibilities are covered and I don’t have to get it right.
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