Tag Archives: Operation

[Solved] NTP Sync common error: no server suitable for synchrnization found

Project Scene:

Environment centos7.9


Problem description

Set a server as ntp server. The other is the client. Found an error. no server suitable for synchrnization found

Use: ntpdate -d 10.143.33.50

View the error

xxx.xxx.xxx.xxx: Server dropped: no data

Appears again during debugging

xxx.xxx.xxx.xxx: server dropped: strata too high


Cause Analysis:

1. Keepalived was originally installed on the server. I thought it was because of this effect. After closing it, the problem is still there.

2,–check from the server side
[root@timeserver ~]# ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
210.72.145.44 .ACTS. 1 u 971 8 0 0.000 0.000 0.000
202.120.2.101 .INIT. 10 u 8 64 377 0.000 0.000 0.000

Viewing is normal.

3, there may be network reasons

4. From the data, it is also related to conf. configuration , configuration such as restrict


Solution:

1. Make sure port 123 is connected

2. Modify the server configuration (202.120.2.101 This is the synchronization server)

vim /etc/ntp.conf

restrict default nomodify notrap noquery
restrict 127.0.0.1
server 202.120.2.101 prefer
server 127.127.1.0
fudge 127.127.1.0 stratum 10
driftfile /var /lib/ntp/drift
keys /etc/ntp/keys

3. Restart ntpd on the server side

service ntpd restart

Sendmail config error: mail loops back to me (MX problem?) solution

Yesterday, I didn’t have this problem. After one night, Sendmail reported this error by sending an internal email. Remember yesterday, it just added SMTP authentication, so it has nothing to do with this loops back.
 
Add the local domain name in local-host-Names, don’t bring mail, restart the Sendmail service, and everything is fine. Many online solutions require changes to your HOSTS, and I haven’t changed either.