Chrony, PTP, Network Time Security (NTS, NTPsec) to replace unsecure/old NTP (ntpd)

johnpoz

@mer agree.. If your not a fan of the defaults - change them.. Defaults are almost always what they are to minimize chance of it not working.. What is the most basic config I can put in - that pretty much a given it will "work". That is the default..

Nobody says that default working config = secure ;)

While I agree as something like pfsense matures and stuff its using evolves - defaults change, and old non secure stuff can drop off. I do recall not that long ago some issues people were having because the changed and dropped off some ssh ciphers from the default config - which broke some users access via their ssh clients, because their clients were out dated, etc.

Default broke shit ;) heheh atleast from the users point of view.. I don't see pretty much anything be it ntp, ssh, web being locked down to tightest mos secure best practice from a security point of view for defaults.. Because its less likely to just work out of the box - which when it doesn't work out of the box, users not happy ;)

bingo600

@johnpoz said in [Network Time Security (NTS, NTPsec) to replace

I wouldn't in a million years provide such a service off my firewall to the public internet, ntp on pfsense is meant for ntp server for your local network.

I totally agree here.
When i worked w. PIX/ASA , there was a sntp client , no NTP service.

In fact NTP service prob. doesn't belong on a firewall , just a sync client. pointing to an inside NTP server.

And if I was going to provide it as public service - I would make sure I go through its config, etc. To make sure nothing stupid is in there ;)

The last OOPZ i know about in NTPD was the amplification attack,
and that is easily avoided in the setup today.

And i agree with : What security issues needs to be fixed in NTP right now ?

/Bingo

AndyRH

I think the security question must be narrowed to have relevance.
NTP sends the time in clear text. (Time is not a secret)
NTP does not validate who it is talking to. (In theory you could use this to be mean to someone, NTP has a sanity check on time changes, check those defaults!)
NTP service has no known vulnerabilities at this time. (Software is secure)
It is simple to use and hard to mess up, does that help security?

johnpoz

@andyrh nice way to look at it.. I concur!

DaddyGo

@sergei_shablovsky

an evasive post but important: (for all :))

I recommend it to all who to use GPSD based stratum1 NTP - follow and update guidelines!!! (on your network NTP source)

https://www.theregister.com/2021/10/19/gpsd_bug_reset/

we run it and it affects our settings:
https://www.ntpsec.org/white-papers/stratum-1-microserver-howto/#RASPBIAN

the biggest thanks to Gary Miller and others

Sergei_Shablovsky

@daddygo said in Network Time Security (NTS, NTPsec) to replace unsecure/old NTP (ntpd):

I recommend it to all who to use GPSD based stratum1 NTP - follow and update guidelines!!! (on your network NTP source)
https://www.theregister.com/2021/10/19/gpsd_bug_reset/
we run it and it affects our settings:
https://www.ntpsec.org/white-papers/stratum-1-microserver-howto/#RASPBIAN

Let's to remind very old but useful Network Time Protocol: Best Practices White Paper

Sergei_Shablovsky

@andyrh said in Network Time Security (NTS, NTPsec) to replace unsecure/old NTP (ntpd):

NTP service has no known vulnerabilities at this time. (Software is secure)
It is simple to use and hard to mess up, does that help security?

“If something in Internet was not already hacked, this is not because it’s strong, it’s because till this time no one pay serious attention on this “something”(c)myself

No one goes deeply and care about how this old things working, but only after a lot of crashes, transporting issues, and some quantity of broken peoples lifes community starting SLOWLY changing mindset about needs to keep up to date old protocols that used in billions devices from your coffee maker, heart cardio stimulator, cars to blood pumps, very big oil & gas sea tankers, citie's energy stations, etc...

DaddyGo

@sergei_shablovsky said in Network Time Security (NTS, NTPsec) to replace unsecure/old NTP (ntpd):

it’s because till this time no one pay serious attention on this “something”(me)

Hmmm, that's a serious formula, but just think of all the stratum1 satellites... (there are a few of them)
The NTP is currently massive....
(but like everything else it may be vulnerable)

everything would be dead without it, think of the stock exchange, credit card transactions that are dampened by prime number encryption and much more....

BTW:
use your power for good things

mer

I feel like I am missing something here.
Synchronizing time across the network, even if a single server and single client, means what?
client asks a configured server "what time do you think it is" and then applies alogrithms on the reply.

Security wise:
What level of trust does the client have for the server it's asking? One would think the client shouldn't be configured to as clients it doesn't trust.

Granted:
NTP servers typically are open, so anyone can ask them, which could result in DOS from the server. But "so what"? Client can't talk to a server?

So: I think a lot of this discussion is based on standing up a server not simply being a client.
If your pfSense box is going to have an independent time source at stratum 1, of course make it so only your desired clients (your network) use it as a definitive source of time.

JKnott

@mer

One thing to remember is you can set up NTP with multiple sources. You should have at least 3, so that if one starts providing bad data, then it will be ignored. This makes it difficult to tamper with.

I have 5 sources, 3 of which are stratum 1 and 2 stratum 2.

Sergei_Shablovsky

@daddygo said in Network Time Security (NTS, NTPsec) to replace unsecure/old NTP (ntpd):

@sergei_shablovsky said in Network Time Security (NTS, NTPsec) to replace unsecure/old NTP (ntpd):

it’s because till this time no one pay serious attention on this “something”(me)

use your power for good things

Sorry my misstyping, I mean that’s phrase made by myself. :)

Sergei_Shablovsky

@bingo600 said in Network Time Security (NTS, NTPsec) to replace unsecure/old NTP (ntpd):

If i was to change from NTP, to something "Brand new". I would prob. consider Chrony instead.

Thank You again one time for suggestion.

Just for anyone this Comparison of NTP implementations

Ok, I agree with You: for various reasons (some of it are very valuable like less dependent from main CPU frequency changes (because power management enabled in BIOS), link delay/jitter/lost packets, noticeable working speed,...) the Chrony looks like more logical solution both for NTP client & server.

bingo600

@sergei_shablovsky
Even though Chrony is "Shining Brand New" , i would .. As it is the industry standard.
Still prefer NTP to be the timeserver on pfSense

Chrony would be something i'd play with on a separate host , if i wanted to.

/Bingo

Patch

@bingo600 said in Network Time Security (NTS, NTPsec) to replace unsecure/old NTP (ntpd):

Even though Chrony is "Shining Brand New" , i would .. As it is the industry standard.
Still prefer NTP to be the timeserver on pfSense

Imo Chrony is just plan better and can see no reason not to use it on pfsense

Time synchronisation is better (faster and more accurate synchronisation)
Better reporting via the combination of

chronyc tracking
chronyc sources
chronyc sourcestats
chronyc clients

So I would like to see chrony on pfsense. For me it would be cleaner than using my Proxmox host for chrony / site time.

Sergei_Shablovsky

@patch Even more:

chrony vs ntp
Things chrony can do better than ntp:

chrony can perform usefully in an environment where access to the time reference is intermittent. ntp needs regular polling of the reference to work well.

chrony can usually synchronise the clock faster and with better time accuracy.

chrony quickly adapts to sudden changes in the rate of the clock (e.g. due to changes in the temperature of the crystal oscillator). ntp may need a long time to settle down again.

chrony can perform well even when the network is congested for longer periods of time.

chrony in the default configuration never steps the time to not upset other running programs. ntp can be configured to never step the time too, but in that case it has to use a different means of adjusting the clock (daemon loop instead of kernel discipline), which may have a negative effect on accuracy of the clock.

chrony can adjust the rate of the clock in a larger range, which allows it to operate even on machines with broken or unstable clock (e.g. in some virtual machines).

chrony is smaller, it uses less memory and it wakes up the CPU only when necessary, which is better for power saving.

Things chrony can do that ntp can’t:

chrony supports the Network Time Security (NTS) authentication mechanism.

chrony supports hardware timestamping on Linux, which allows an extremely stable and accurate synchronisation in local network.

chrony provides support for isolated networks whether the only method of time correction is manual entry (e.g. by the administrator looking at a clock). chrony can look at the errors corrected at different updates to work out the rate at which the computer gains or loses time, and use this estimate to trim the computer clock subsequently.

chrony provides support to work out the gain or loss rate of the real-time clock, i.e. the clock that maintains the time when the computer is turned off. It can use this data when the system boots to set the system time from a corrected version of the real-time clock. These real-time clock facilities are only available on Linux, so far.

Things ntp can do that chrony can’t:

ntp supports all operating modes from RFC 5905, including broadcast, multicast, and manycast server/client. However, the broadcast and multicast modes are inherently less accurate and less secure (even with authentication) than the ordinary server/client mode, and should generally be avoided.

ntp supports the Autokey protocol (RFC 5906) to authenticate servers with public-key cryptography. Note that the protocol has been shown to be insecure and has been obsoleted by NTS (RFC 8915).

ntp has been ported to more operating systems.

ntp includes a large number of drivers for various hardware reference clocks. chrony requires other programs (e.g. gpsd or ntp-refclock) to provide reference time via the SHM or SOCK interface.

Sergei_Shablovsky

@bingo600

Please describe step-by-step how to properly installing Chrony on pfSense.

Thank You so much!

Sergei_Shablovsky

@patch said in Network Time Security (NTS, NTPsec) to replace unsecure/old NTP (ntpd):

So I would like to see chrony on pfsense. For me it would be cleaner than using my Proxmox host for chrony / site time.

How to ask (with a positive result, of course), the pfSense dev team about including Chrony as package ?

Because in comparison “Chrony vs ntpd”, the Chrony are the winner no doubt.

bingo600

@sergei_shablovsky said in Network Time Security (NTS, NTPsec) to replace unsecure/old NTP (ntpd):

@bingo600

Please describe step-by-step how to properly installing Chrony on pfSense.

Thank You so much!

As I wrote , i would do it on a separate host.
And my preferred target would be a linux (Debian 10)

/Bingo

johnpoz

@bingo600 said in Network Time Security (NTS, NTPsec) to replace unsecure/old NTP (ntpd):

would do it on a separate host.

Yeah I am agreement here - while pfsense can do many amazing things, and can run quite a few different services for your network from just a home setup to enterprise level.

Doesn't always mean its the best thing for every job.. If the ntp features do not fit into your wants/needs for your network. Then run ntp on something else..

There could be many reasons why your pfsense box is not the best fit for your networks stable ntp source. For starters - its load will fluctuate as your network runs traffic through it at vary levels throughout the day, other services you might be running on it already can and will effect its temp as loads on those fluctuate.. Depending on what hardware your running it on - might not be suited for say PPS input, etc. This sort of stuff does not make for the most accurate and stable time source - if what your looking for is dead nuts time within a few ms or even nanoseconds :)

If your goal is highly reliable highly accurate ntp source.. Running it on something else is prob going to be best bang for the buck here. Not saying you can not provide ntp from pfsense - but its not all that costly or involved to provide a much better source for your network on something else.. This will give you wide choice in actual time software used, better hardware for time, if all it does provide time, is overall load and temp can be better controlled for more accurate time keeping.. etc..

Sergei_Shablovsky

@johnpoz said in Network Time Security (NTS, NTPsec) to replace unsecure/old NTP (ntpd):

@bingo600 said in Network Time Security (NTS, NTPsec) to replace unsecure/old NTP (ntpd):

would do it on a separate host.

Yeah I am agreement here - while pfsense can do many amazing things, and can run quite a few different services for your network from just a home setup to enterprise level.

We all love pfSense software, because this we all are here. :)

Doesn't always mean its the best thing for every job.. If the ntp features do not fit into your wants/needs for your network. Then run ntp on something else..

Let’s note, the ACCURATE TIMESTAMP is one of the core things in processing on fw/main gate. This is not something we may name “extra” or “additional”. This is core.

There could be many reasons why your pfsense box is not the best fit for your networks stable ntp source. For starters - its load will fluctuate as your network runs traffic through it at vary levels throughout the day, other services you might be running on it already can and will effect its temp as loads on those fluctuate.. Depending on what hardware your running it on - might not be suited for say PPS input, etc. This sort of stuff does not make for the most accurate and stable time source - if what your looking for is dead nuts time within a few ms or even nanoseconds :)

At this point Let me to be disagreeing with You: in most cases pfSense running on separate server, powerful, with 2 PSU and several WANs to avoid outage.
And of course, FreeBSD daemon to work with PPS source like GPS receiver thru the COM port - eating only smallest fraction of total CPU power and interrupts. So, running You this NTP service + GPS on COM port or not - not making impact on whole system.

If your goal is highly reliable highly accurate ntp source.. Running it on something else is prob going to be best bang for the buck here.
As I note several post before, there are several BIG disadvantages of this:

round trip to other node and back (thru the switch, other system drivers, etc..) impact on accuracy of timestamp. Because the are measurement in milliseconds / nanoseconds;
you need care about extra one server (time server), this mean double PSU, double Eth connection, best available servers hardware, memory, enterprise (mean big MTBF hours), etc...

Not saying you can not provide ntp from pfsense - but its not all that costly or involved to provide a much better source for your network on something else.. This will give you wide choice in actual time software used, better hardware for time, if all it does provide time, is overall load and temp can be better controlled for more accurate time keeping.. etc..

Another time not agree: now are quite little a choice, ntpd or Chrony. Please look at the comparison table.