# Problem with IPv4 servers **URL:** \ **Category:** Server operators\ **Created:** [January 22, 2021, 6:04pm UTC](https://community.ntppool.org/t/problem-with-ipv4-servers/1894 "2021-01-22T18:04:29Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![jfrater](https://sea2.discourse-cdn.com/flex016/user_avatar/community.ntppool.org/jfrater/32/109_2.png) [@jfrater](https://community.ntppool.org/u/jfrater)\ **Post date:** [January 22, 2021, 6:04pm UTC](https://community.ntppool.org/t/problem-with-ipv4-servers/1894/1 "2021-01-22T18:04:29Z")
Hi, About a week ago, the IPv4 part of the servers stoped working for the pool. But they do work, I know this because I you them via IPv4 for hundreds of devices here. Also IPv6 still works fine. I thought it may have been a firewall issue, but dont find any blocks that would affect it, plus they appear reachable by ntppool: ``` Traceroute to 200.59.16.50 1 (139.178.64.41) AS54825 47.081 47.038 ``` … 16 (186.176.7.74) AS20299 71.028 70.977 17 [ntp3.fratec.net](http://ntp3.fratec.net) (200.59.16.50) AS262149 82.264 83.180 another one: Traceroute to 200.59.21.5 1 (139.178.64.41) AS54825 47.131 47.077 … 16 (200.59.17.43) AS262149 73.008 16 [www.fratec.net](http://www.fratec.net) (200.59.21.5) AS262149 81.316 Still they all give timeout to Newark Monitoring Station: ts\_epoch,ts,offset,step,score,leap,error 1611337815,“2021-01-22 17:50:15”,0,-5,-100,“i/o timeout” 1611336733,“2021-01-22 17:32:13”,0,-5,-100,“i/o timeout” 1611335662,“2021-01-22 17:14:22”,0,-5,-100,“i/o timeout” 1611334581,“2021-01-22 16:56:21”,0,-5,-100,“i/o timeout” 1611333499,“2021-01-22 16:38:19”,0,-5,-100,“i/o timeout” 1611332422,“2021-01-22 16:20:22”,0,-5,-100,“i/o timeout” 1611331355,“2021-01-22 16:02:35”,0,-5,-100,“i/o timeout” 1611330291,“2021-01-22 15:44:51”,0,-5,-100,“i/o timeout” 1611329218,“2021-01-22 15:26:58”,0,-5,-100,“i/o timeout” 1611328121,“2021-01-22 15:08:41”,0,-5,-100,“i/o timeout” ### 200.59.16.50 Puntuación actual: -100.0 (sólo los servidores con una puntuación mayor que 10 se usan en el equipo) ### History 12Thu 2112Fri 2212200-20-50-100Offset monitoring and scores for 200.59.16.50 Monitoring Station:Newark, NJ, US (-100) What can I do to find the problem here? Whats Newarks IP so I can monitor it? ---
**Author:** ![stevesommars](https://sea2.discourse-cdn.com/flex016/user_avatar/community.ntppool.org/stevesommars/32/2075_2.png) [@stevesommars](https://community.ntppool.org/u/stevesommars)\ **Post date:** [January 22, 2021, 6:38pm UTC](https://community.ntppool.org/t/problem-with-ipv4-servers/1894/2 "2021-01-22T18:38:59Z")
Newark is 139.178.64.42 and hasn’t seen any NTP responses from 200.59.16.50 since 2021-01-13 19:52 UTC ping and default traceroute from Newark reach the NTP server, but NTP isn’t getting through. However when I try traceroute from Newark to the NTP server using destination UDP port 123 I see a routing loop. traceroute -p 123 200.59.16.50 traceroute to 200.59.16.50 (200.59.16.50), 30 hops max, 60 byte packets 1 gateway (139.178.64.41) 16.146 ms 16.104 ms 16.068 ms 2 \* \* \* 3 [0.ae3.bsr2.ewr1.packet.net](http://0.ae3.bsr2.ewr1.packet.net) (198.16.4.214) 0.898 ms 0.888 ms [0.ae2.bsr2.ewr1.packet.net](http://0.ae2.bsr2.ewr1.packet.net) (198.16.4.212) 0.868 ms 4 [0.et-0-0-7.bsr1.ewr2.packet.net](http://0.et-0-0-7.bsr1.ewr2.packet.net) (198.16.7.207) 7.634 ms 7.612 ms 7.589 ms 5 [nyk-b2-link.telia.net](http://nyk-b2-link.telia.net) (62.115.175.182) 0.980 ms 0.959 ms 0.916 ms 6 [nyk-bb3-link.ip.twelve99.net](http://nyk-bb3-link.ip.twelve99.net) (213.155.130.29) 33.017 ms 33.031 ms 33.267 ms 7 [rest-bb1-link.ip.twelve99.net](http://rest-bb1-link.ip.twelve99.net) (62.115.141.244) 8.424 ms 8.652 ms 8.633 ms 8 [boca-b2-link.ip.twelve99.net](http://boca-b2-link.ip.twelve99.net) (62.115.123.29) 32.725 ms 33.140 ms 32.860 ms 9 [asurnet-svc071312-ic357662.c.telia.net](http://asurnet-svc071312-ic357662.c.telia.net) (62.115.40.211) 33.441 ms 32.936 ms [boca-b2-link.ip.twelve99.net](http://boca-b2-link.ip.twelve99.net) (62.115.118.162) 34.795 ms 10 [asurnet-svc071312-ic357662.c.telia.net](http://asurnet-svc071312-ic357662.c.telia.net) (62.115.40.211) 34.403 ms [ae0.nmi-mx2020-2.north-miami.fl.usa.cwc.com](http://ae0.nmi-mx2020-2.north-miami.fl.usa.cwc.com) (69.79.102.1) 34.251 ms 36.951 ms 11 69.79.106.49 (69.79.106.49) 56.646 ms 56.676 ms 56.914 ms 12 \* \* \* 13 \* \* \* 14 \* \* \* 15 [sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net](http://sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net) (200.59.17.43) 71.076 ms 71.397 ms 76.491 ms 16 [ether1.mikrotik-bb-desa1.fratec.net](http://ether1.mikrotik-bb-desa1.fratec.net) (200.59.19.50) 81.921 ms 86.875 ms 86.891 ms 17 [sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net](http://sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net) (200.59.17.43) 71.280 ms 69.935 ms 71.293 ms 18 [ether1.mikrotik-bb-desa1.fratec.net](http://ether1.mikrotik-bb-desa1.fratec.net) (200.59.19.50) 87.502 ms 80.816 ms 82.226 ms 19 [sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net](http://sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net) (200.59.17.43) 71.312 ms 71.922 ms 71.448 ms 20 [ether1.mikrotik-bb-desa1.fratec.net](http://ether1.mikrotik-bb-desa1.fratec.net) (200.59.19.50) 87.060 ms 80.977 ms 81.961 ms 21 [sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net](http://sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net) (200.59.17.43) 71.446 ms 71.997 ms 71.368 ms 22 [ether1.mikrotik-bb-desa1.fratec.net](http://ether1.mikrotik-bb-desa1.fratec.net) (200.59.19.50) 82.522 ms 81.859 ms 80.975 ms 23 [sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net](http://sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net) (200.59.17.43) 72.252 ms 76.857 ms 71.455 ms 24 [ether1.mikrotik-bb-desa1.fratec.net](http://ether1.mikrotik-bb-desa1.fratec.net) (200.59.19.50) 83.103 ms 82.473 ms 82.673 ms 25 [sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net](http://sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net) (200.59.17.43) 70.460 ms 76.790 ms 71.122 ms 26 [ether1.mikrotik-bb-desa1.fratec.net](http://ether1.mikrotik-bb-desa1.fratec.net) (200.59.19.50) 81.270 ms 82.499 ms 82.464 ms 27 [sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net](http://sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net) (200.59.17.43) 71.698 ms [ether1.mikrotik-bb-desa1.fratec.net](http://ether1.mikrotik-bb-desa1.fratec.net) (200.59.19.50) 83.564 ms [sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net](http://sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net) (200.59.17.43) 76.740 ms 28 [ether1.mikrotik-bb-desa1.fratec.net](http://ether1.mikrotik-bb-desa1.fratec.net) (200.59.19.50) 83.490 ms 84.334 ms 83.422 ms 29 [sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net](http://sfp-sfpplus1.mikrotik-bb-router-gnd1.fratec.net) (200.59.17.43) 72.663 ms 70.875 ms 77.155 ms 30 [ether1.mikrotik-bb-desa1.fratec.net](http://ether1.mikrotik-bb-desa1.fratec.net) (200.59.19.50) 87.484 ms 87.406 ms 83.805 ms ---
**Author:** ![jfrater](https://sea2.discourse-cdn.com/flex016/user_avatar/community.ntppool.org/jfrater/32/109_2.png) [@jfrater](https://community.ntppool.org/u/jfrater)\ **Post date:** [January 22, 2021, 7:01pm UTC](https://community.ntppool.org/t/problem-with-ipv4-servers/1894/3 "2021-01-22T19:01:41Z")
> [@stevesommars](#): > > 139.178.64.42 I just rebooted one of the routers so that may have coused the loop, but I can reach Newark from that server just fine: root@stratum1:~# traceroute 139.178.64.42 traceroute to 139.178.64.42 (139.178.64.42), 30 hops max, 60 byte packets 1 [ether3.mikrotik-bb-zeus.fratec.net](http://ether3.mikrotik-bb-zeus.fratec.net) (200.59.16.33) 0.193 ms 0.152 ms 0.156 ms 2 186.176.7.73 (186.176.7.73) 0.745 ms 0.793 ms 0.766 ms 3 186.32.0.217 (186.32.0.217) 1.012 ms 1.007 ms 1.018 ms 4 \* 190.106.192.237 (190.106.192.237) 52.398 ms \* 5 [mai-b1-link.telia.net](http://mai-b1-link.telia.net) (62.115.56.164) 40.884 ms 42.800 ms 51.117 ms 6 [ash-bb2-link.ip.twelve99.net](http://ash-bb2-link.ip.twelve99.net) (62.115.120.176) 82.645 ms 72.525 ms [rest-bb1-link.ip.twelve99.net](http://rest-bb1-link.ip.twelve99.net) (62.115.119.230) 68.002 ms 7 \* [nyk-bb3-link.ip.twelve99.net](http://nyk-bb3-link.ip.twelve99.net) (62.115.141.245) 76.663 ms \* 8 [nyk-b2-link.ip.twelve99.net](http://nyk-b2-link.ip.twelve99.net) (62.115.137.99) 71.674 ms 71.693 ms [nyk-b2-link.ip.twelve99.net](http://nyk-b2-link.ip.twelve99.net) (213.155.130.28) 71.854 ms 9 [packethost-ic-345229-nyk-b2.c.telia.net](http://packethost-ic-345229-nyk-b2.c.telia.net) (62.115.175.183) 83.129 ms 82.109 ms 71.260 ms 10 [0.et-0-0-7.bsr2.ewr1.packet.net](http://0.et-0-0-7.bsr2.ewr1.packet.net) (192.80.8.10) 71.881 ms 82.375 ms [0.et-0-0-1.bsr1.ewr1.packet.net](http://0.et-0-0-1.bsr1.ewr1.packet.net) (198.16.7.206) 74.278 ms 11 [0.ae2.dsr1.ewr1.packet.net](http://0.ae2.dsr1.ewr1.packet.net) (198.16.4.213) 90.639 ms [0.ae2.dsr2.ewr1.packet.net](http://0.ae2.dsr2.ewr1.packet.net) (198.16.4.215) 84.180 ms 95.069 ms 12 147.75.98.105 (147.75.98.105) 103.039 ms 87.503 ms 86.315 ms 13 [monewr1.ntppool.net](http://monewr1.ntppool.net) (139.178.64.42) 77.766 ms 78.827 ms 88.124 ms ---
**Author:** ![jfrater](https://sea2.discourse-cdn.com/flex016/user_avatar/community.ntppool.org/jfrater/32/109_2.png) [@jfrater](https://community.ntppool.org/u/jfrater)\ **Post date:** [January 22, 2021, 7:09pm UTC](https://community.ntppool.org/t/problem-with-ipv4-servers/1894/4 "2021-01-22T19:09:12Z")
Rebooting the router did give a clue: ts\_epoch,ts,offset,step,score,leap,error 1611342156,“2021-01-22 19:02:36”,0,-5,-94.3,“i/o timeout” 1611341063,“2021-01-22 18:44:23”,-0.003019731,1,-94,0, 1611340001,“2021-01-22 18:26:41”,0,-5,-100,“i/o timeout” while that link was down Newark did get an answer. Could it be that Newark needs the NTP packet to enter / exit from the same provider on my end? I’ll do some more testing ---
**Author:** ![stevesommars](https://sea2.discourse-cdn.com/flex016/user_avatar/community.ntppool.org/stevesommars/32/2075_2.png) [@stevesommars](https://community.ntppool.org/u/stevesommars)\ **Post date:** [January 22, 2021, 7:57pm UTC](https://community.ntppool.org/t/problem-with-ipv4-servers/1894/5 "2021-01-22T19:57:42Z")
From 18:41 - 18:48 I saw NTP responses getting through. Now I’m seeing repeatable NTP blockage. I’ll characterize it over the next couple of hours. ---
**Author:** ![jfrater](https://sea2.discourse-cdn.com/flex016/user_avatar/community.ntppool.org/jfrater/32/109_2.png) [@jfrater](https://community.ntppool.org/u/jfrater)\ **Post date:** [January 22, 2021, 9:47pm UTC](https://community.ntppool.org/t/problem-with-ipv4-servers/1894/6 "2021-01-22T21:47:33Z")
Just in case I tested from other networks and it works fine, for example: [https://keetweej.vanheusden.com/query\_ntp\_do2.php?host=ntp3.fratec.net](https://keetweej.vanheusden.com/query_ntp_do2.php?host=ntp3.fratec.net) ---
**Author:** ![stevesommars](https://sea2.discourse-cdn.com/flex016/user_avatar/community.ntppool.org/stevesommars/32/2075_2.png) [@stevesommars](https://community.ntppool.org/u/stevesommars)\ **Post date:** [January 22, 2021, 10:09pm UTC](https://community.ntppool.org/t/problem-with-ipv4-servers/1894/7 "2021-01-22T22:09:49Z")
There is a hard block for port 123 at “COLUMBUS-NETWORKS”. Are you able to change routing from your side? # Use ntp port, 123 $ traceroute -n -U -p 123 200.59.16.50 traceroute to 200.59.16.50 (200.59.16.50), 30 hops max, 60 byte packets 1 139.178.64.41 21.376 ms 21.321 ms 21.292 ms 2 \* \* \* 3 198.16.4.208 2.413 ms 198.16.4.212 0.785 ms 198.16.4.214 0.771 ms 4 198.16.7.207 1.546 ms 192.80.8.11 1.791 ms 198.16.7.207 1.761 ms 5 62.115.175.182 0.953 ms 0.918 ms 1.149 ms 6 213.155.130.29 33.071 ms 32.921 ms 33.131 ms 7 62.115.141.244 8.850 ms 8.394 ms 9.032 ms 8 62.115.123.29 32.779 ms 32.724 ms 33.179 ms 9 62.115.40.211 33.081 ms 33.130 ms 32.946 ms 10 69.79.102.1 34.182 ms 33.978 ms 33.953 ms 11 \* \* \* 12 \* \* \* 13 \* \* \* 14 \* \* \* 15 \* \* \* 16 \* \* \* 17 \* \* \* 18 \* \* \* 19 \* \* \* 20 \* \* \* 21 \* \* \* 22 \* \* \* 23 \* \* \* etc. # Use a non-NTP port, 124 $ traceroute -n -U -p 124 200.59.16.50 traceroute to 200.59.16.50 (200.59.16.50), 30 hops max, 60 byte packets 1 139.178.64.41 14.005 ms 13.962 ms 13.925 ms 2 \* \* \* 3 198.16.4.210 0.772 ms 198.16.4.214 0.966 ms 1.192 ms 4 192.80.8.11 1.322 ms 198.16.7.207 1.379 ms 1.604 ms 5 62.115.175.182 1.072 ms 1.295 ms 1.252 ms 6 213.155.130.29 32.912 ms 33.096 ms 32.913 ms 7 62.115.141.244 8.853 ms 9.124 ms 8.230 ms 8 62.115.123.29 33.177 ms 32.900 ms 33.112 ms 9 62.115.40.211 32.983 ms 33.465 ms 33.058 ms 10 69.79.102.1 34.363 ms 34.151 ms 34.108 ms 11 69.79.106.49 57.177 ms 56.620 ms 69.79.102.1 35.647 ms 12 \* \* \* 13 \* \* \* 14 \* \* \* 15 186.179.72.111 89.845 ms 89.896 ms 89.618 ms 16 200.59.17.41 90.921 ms 85.760 ms 90.876 ms 17 200.59.16.50 87.105 ms 87.076 ms 81.892 ms Look at ownership: 54825 | 198.16.4.210 | 198.16.4.0/22 | US | arin | 2012-09-05 | PACKET, US 54825 | 192.80.8.11 | 192.80.8.0/24 | US | arin | 2014-12-17 | PACKET, US 1299 | 62.115.175.182 | 62.115.0.0/16 | SE | ripencc | 2001-08-09 | TELIANET Telia Carrier, SE 1299 | 213.155.130.29 | 213.155.128.0/19 | SE | ripencc | 2000-02-18 | TELIANET Telia Carrier, SE 1299 | 62.115.141.244 | 62.115.0.0/16 | SE | ripencc | 2001-08-09 | TELIANET Telia Carrier, SE 1299 | 62.115.123.29 | 62.115.0.0/16 | SE | ripencc | 2001-08-09 | TELIANET Telia Carrier, SE 1299 | 62.115.40.211 | 62.115.0.0/16 | SE | ripencc | 2001-08-09 | TELIANET Telia Carrier, SE 23520 | 69.79.102.1 | 69.79.102.0/24 | US | arin | 2003-09-24 | COLUMBUS-NETWORKS, US 23520 | 69.79.106.49 | 69.79.106.0/24 | US | arin | 2003-09-24 | COLUMBUS-NETWORKS, US