[EMAIL PROTECTED] (Luc Pardon) writes:

> Well, I'm about to give up.
>
> My logs are getting flooded with "Connection refused" messages and I can't 
> find why, much less how to stop them.
>
> This is a rather oldish RH Linux box with two network cards. One is connected 
> to the bad world outside via an ADSL router, the other to the internal 
> network (192.168.x.x). It gets its time from stratum 2 servers and provides 
> time to the internal network.
>
> I've been running ntp on that box since 2001. In June 2005, I upgraded to ntp 
> 4.2.0.
>
> Life was beautiful for more than a year until, last week, I suddenly started 
> getting "Connection refused" messages in syslog.
>
>  > Sep  3 04:06:32 gida ntpd[4796]: recvfrom(193.190.230.65) fd=9: Connection 
> refused
>  > Sep  3 04:06:32 gida ntpd[4796]: recvfrom(193.190.230.65) fd=9: 
> Connection refused
This error message from the kernel is a bit unusual, but you said it was 
running on Linux...

>
> This is because I checked the mailing list and decided to upgrade to 4.2.2p3. 
> Almost as soon as I started the new version, the "connection refused" was 
> back, but different now:
>
>  > Sep  7 09:24:25 gida ntpd[26405]: ntpd [EMAIL PROTECTED] Thu Sep  7 
> 07:05:22 UTC
>  > 2006 (1)
>  > Sep  7 09:24:25 gida ntpd[26406]: precision = 1.000 usec
>  > Sep  7 09:24:25 gida ntpd: ntpd startup succeeded
>  > Sep  7 09:24:26 gida ntpd[26406]: Listening on interface wildcard, 
> 0.0.0.0#123 Disabled
>  > Sep  7 09:24:26 gida ntpd[26406]: Listening on interface lo, 
> 127.0.0.1#123 Enabled
>  > Sep  7 09:24:26 gida ntpd[26406]: Listening on interface eth0, 
> 192.168.1.23#123
>  > Enabled
>  > Sep  7 09:24:26 gida ntpd[26406]: Listening on interface eth1, 
> 192.168.254.2#123 Enabled
>  > Sep  7 09:24:26 gida ntpd[26406]: kernel time sync status 0040
>  > Sep  7 09:24:32 gida ntpd[26406]: frequency initialized 128.381 PPM from 
> /etc/ntp/drift
>  > Sep  7 09:24:32 gida ntpd[26406]: recvfrom(0.0.0.0) fd=51: Connection 
> refused
>
>    Note that, at startup, it says "Listening on interface wildcard, 
> 0.0.0.0#123 Disabled" but that seems a blatant lie since lsof shows that it 
> does have a socket open there.
>
The socket being bound does not allow you to call that a lie. The Disabled 
information just documents that pakets received on that
socket will be discarded.

>    The 'refused' messages come two at a time and in 64 second intervals.
>
So it seems to be related with some query activity.

>    I tried adding a line 'manycastclient 224.1.1.1' to ntp.conf. The messages 
> stopped and came back. So it doesn't make a difference.
>
>    I tried removing the 'restrict' lines from ntp.conf but it doesn't make a 
> difference.
restrict is not related to this behavior.

>
>    I then pulled 4.2.3p39 from dev and tried again. Same thing, the only 
> difference is that it doesn't mention the wildcard IF at startup.
>
>    I noticed that 193.190.230.66 is a stratum 1 server and not a 2 like the 
> others. Either I missed that when I added it to ntp.conf in May 2005 or they 
> changed from 2 to 1 since then. In any case I removed it but it doesn't make 
> any difference.
>
>    I tried the debug output but it doesn't tell me anything. All I can make 
> of it is that there is only one 'refused' in the debug output and two in the 
> syslog. Also, the 'refused' comes after several seconds of silence in the 
> debug output. It doesn't tell me why it thinks it should call recvfrom.
The socket seems to be ready for reading (select && SIGIO). when ntpd reads 
from it it gets the error message from the kernel. As I said getting that on a 
recvfrom is unusal
and delivered from the kernel - ntpd just documents that.

>
>    Needless to say, "tcpdump -i eth1 port ntp" (eth1 being fd 51) doesn't 
> show activity that might be related to the refusals.
I suspect that icmp messages (probably port unreachable) being received. So try 
"tcpdump -i eth1 port ntp or icmp" and see whether
such icmp messages show up and who sends them.

>
>    One thing that I should add is that I can't ntpq locally on that machine. 
> It  says "Name or service not known". From what I can see with strace it 
> seems to be looking in /etc/services from something. But I wouldn't know 
> what, "ntp" is definitely in there. In any case, this started happening one 
> year ago so it should have nothing to do with the "refused" messages (but 
> maybe with the ntp 4.1.x to 4.2.x transition). I can query the box remotely, 
> from another Linux, without problems.
This looks like a local setup problem other system have following line in 
/etc/services:
ntp             123/udp                         # Network Time Protocol

Frank

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