Cannot sync network time (NTP) on Win10 on BSNL FTTH

  • Thread starter Thread starter vishalrao
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Adithya said:
@vishalrao does NTP work on phone? Maybe this is a windows issue.
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Yes it's a windows behavior, see my earlier post about looking at wireshark tool info. Works on Linux.

But it works on windows when I use airtel 4g wifi Hotspot hence it's really a bsnl firewall configuration issue on the server side
 
Interesting and can happen due to firewall-config mistake.
NTP was used as one of the major attack vectors for amplification attacks so many retail ISPs want to block any of their users from hosting an NTP (UDP port 123) service.

Intended rule on the firewall:
Drop traffic going towards UDP port 123 of BSNL retail users (can be defined based on destination IP blocks or simply the router's egress interface)


Likely rule which BSNL might have put (my guess):
Drop traffic coming from UDP port 123. Or drop rule with port 123 in any (source/destination) direction.

BSNL is a large network and for BSNL folks to troubleshoot such rule, one has to share IP pool. Please post WAN IP (you can hide the last block if concerned) and I will pass this thread to friends at BSNL so that can review it. Without knowing IP, it would be hard for them to look across all gateway routers.


Thanks.
 
@shashankb see my earlier posts in this thread, it works on linux and other devices because they use ephemeral port in higher (unprivileged) range above 1024 it seems. on Win10 it is using incoming response ephemeral UDP port 123 itself which seems to be blocked by BSNL at least in Pune NOC. People from other areas like Kerala and North-East seem to not face this issue.

@Anurag Bhatia thank you for your response, my current IP is 117.212.245.185 and I am located in Pune. Note that of course my IP changes every 24 hours or so thanks to my router reconnecting (ONT is in bridge mode) and I sometimes get IP range in 59.x.x.x range.

Thanks again! Cheers!
 
Typically a firewall can/should block incoming server listen ports and not the temporary ephemeral ports used by client communications.
 
I had the same issue since few months, use the above Net Time utility.I had a major problem cause I run windows and hackintosh. So each time I switched they would fuck up the time by hours. This solved the problem for windows..
 
Hi folks,

Can you check again if windows NTP internet time sync is working for you at the moment on Windows 10?

Today I was able to get in touch with Pune NIB/NOC person where I showed the problem I was facing. He said he will escalate to higher ups and reply to my email which I had sent about this issue.

Got a reply on email today evening that "no port 123 is blocked on network - please check ONT port forwarding setting".

Now, I did a factory reset of my ONT and left it in bridge mode with my existing Netgear router and the NTP issue seems to be resolved - at least it is working for more than 30 minutes after reconnecting.

Not sure if they did something in the network or it was really my ONT which started working after factory reset :D

Anyone else still facing this issue? Please mention your location as well.
 
Well I think I spoke (posted) too soon... It's again not working after around 30 minutes post reconnection. Same issue as before.
 
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