[ntp:questions] being rejected

a at b.cd a at b.cd
Sat Oct 9 14:54:54 UTC 2010


David Woolley wrote:

> a at b.cd wrote:
> 
>>>>   1 61694  8000   yes   yes  none    reject
> 
>> assID=61694 status=8000 unreach, conf, no events,
> 
> 
> I don't know why it is saying reach on the assoc, but the rv is
> certainly saying that nothing is coming back, which normally does mean a
> firewall problem.  Often port 123 is firewalled off even though the port
> used for connectivity tests is not.

But the reply packets are comin' thru no problem. I can see them with tcpdump:

# tcpdump -ieth0 -s0 -vvv port ntp
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
16:51:13.668692 IP (tos 0xc0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 76)
    192.168.10.235.ntp > 85.31.187.67.ntp: [bad udp cksum a719!] NTPv4, length 48
        Client, Leap indicator: clock unsynchronized (192), Stratum 0 (unspecified), poll 6s, precision -20
        Root Delay: 0.000000, Root dispersion: 0.000000, Reference-ID: (unspec)
          Reference Timestamp:  0.000000000
          Originator Timestamp: 0.000000000
          Receive Timestamp:    0.000000000
          Transmit Timestamp:   3495624673.668643295 (2010/10/09 14:51:13)
            Originator - Receive Timestamp:  0.000000000
            Originator - Transmit Timestamp: 3495624673.668643295 (2010/10/09 14:51:13)
16:51:13.725737 IP (tos 0x0, ttl 57, id 0, offset 0, flags [DF], proto UDP (17), length 76)
    85.31.187.67.ntp > 192.168.10.235.ntp: [udp sum ok] NTPv4, length 48
        Server, Leap indicator:  (0), Stratum 2 (secondary reference), poll 6s, precision -8
        Root Delay: 0.012069, Root dispersion: 0.032516, Reference-ID: 129.69.1.153
          Reference Timestamp:  3495624222.340305030 (2010/10/09 14:43:42)
          Originator Timestamp: 3495624673.668643295 (2010/10/09 14:51:13)
          Receive Timestamp:    3495624673.882986783 (2010/10/09 14:51:13)
          Transmit Timestamp:   3495624673.883182883 (2010/10/09 14:51:13)
            Originator - Receive Timestamp:  +0.214343518
            Originator - Transmit Timestamp: +0.214539602
16:51:14.668741 IP (tos 0xc0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 76)
    192.168.10.235.ntp > 141.40.103.101.ntp: [bad udp cksum fa90!] NTPv4, length 48
        Client, Leap indicator: clock unsynchronized (192), Stratum 0 (unspecified), poll 6s, precision -20
        Root Delay: 0.000000, Root dispersion: 0.000015, Reference-ID: (unspec)
          Reference Timestamp:  0.000000000
          Originator Timestamp: 0.000000000
          Receive Timestamp:    0.000000000
          Transmit Timestamp:   3495624674.668700516 (2010/10/09 14:51:14)
            Originator - Receive Timestamp:  0.000000000
            Originator - Transmit Timestamp: 3495624674.668700516 (2010/10/09 14:51:14)
16:51:14.716766 IP (tos 0x0, ttl 54, id 0, offset 0, flags [DF], proto UDP (17), length 76)
    141.40.103.101.ntp > 192.168.10.235.ntp: [udp sum ok] NTPv4, length 48
        Server, Leap indicator:  (0), Stratum 2 (secondary reference), poll 6s, precision -20
        Root Delay: 0.006301, Root dispersion: 0.042770, Reference-ID: 134.34.3.18
          Reference Timestamp:  3495622992.015513980 (2010/10/09 14:23:12)
          Originator Timestamp: 3495624674.668700516 (2010/10/09 14:51:14)
          Receive Timestamp:    3495624674.866683959 (2010/10/09 14:51:14)                     
          Transmit Timestamp:   3495624674.866705596 (2010/10/09 14:51:14)                     
            Originator - Receive Timestamp:  +0.197983473                                      
            Originator - Transmit Timestamp: +0.198005080
....

So it really can't be a connectivity issue, can it?




More information about the questions mailing list