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Can ping by hostname but not IP

bostonstaus
bostonstaus asked
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Last Modified: 2020-06-13
I can ping places by hostname but not by ip address.  I am trying to setup an ntp server for my CUCM install. It cant reach the ntp server address i put in. I cant even ping a dns server. I can ping my default gateway and my internet is working fine.
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Paul MacDonaldDirector, Information Systems
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Commented:
Ping a server on the Internet by host name and post the results.  Then ping the same server by IP address and post the results.

What operating system are you using?

Author

Commented:

Edmond HawilaChief Operating Officer
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Commented:
Is IPv4 enabled?

Author

Commented:
Yes.  
Edmond HawilaChief Operating Officer
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Commented:
Please send a screenshot of the result of the below commands:
ping yahoo.com -4

and then ping the ip you get from that.

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Commented:

Andrew Hancock (VMware vExpert PRO / EE Fellow)VMware and Virtualization Consultant
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Commented:
what IP is the NTP server ?

is CUCM a VM hosted on VMware Workstation ?

What network configuration does the VM have ?

Edit the VM, and then edit the Network Interface from VMware Workstation
Edmond HawilaChief Operating Officer
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Commented:
Ok so that works.
Can you do the same for one of your internal ntp server?

Author

Commented:
i dont have an internal ntp server. I am trying to use googles. This is home lab setup.

Edmond HawilaChief Operating Officer
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Commented:
Ok. Give us the screenshot with the server you have the issue with.
Andrew Hancock (VMware vExpert PRO / EE Fellow)VMware and Virtualization Consultant
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Commented:
what is the IP Address ?

Author

Commented:
I am running this from my desktop pc.  
Andrew Hancock (VMware vExpert PRO / EE Fellow)VMware and Virtualization Consultant
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Commented:
so no hypervisor, installed on a Desktop PC ?

Author

Commented:
OH yes sorry.  The pinging i am doing is from my desktop. I am installing CUCM on VMWorkstation. But if i cant ping NTP from my desktop i cant ping it from any VM.

Author

Commented:
It was working fine last night. Nothing has been changed.
Andrew Hancock (VMware vExpert PRO / EE Fellow)VMware and Virtualization Consultant
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Commented:
it's possible the NTP server has gone down, because you are suppose to use DNS names!

what is the IP I'll confirm and try here ?

if you traceroute to the IP Address where dose it fail ?
Edmond HawilaChief Operating Officer
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Commented:
Maybe that specific ntp server has an issue? Have you tried another one? See here:
https://tf.nist.gov/tf-cgi/servers.cgi

Author

Commented:
I am using 216.239.32.15 for NTP server but have also tried others with no success.

Author

Commented:

David Johnson, CDSimple Geek from the '70s
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Commented:
Non-authoritative answer:
Name:    pool.ntp.org
Addresses:  159.203.8.72
          68.69.221.61
          192.99.2.8
          158.69.35.227

Minimum = 120ms, Maximum = 133ms, Average = 126ms

C:\Users\DavidWayneJohnsonCD>ping pool.ntp.org

Pinging pool.ntp.org [95.217.188.206] with 32 bytes of data:
Reply from 95.217.188.206: bytes=32 time=132ms TTL=46
Reply from 95.217.188.206: bytes=32 time=129ms TTL=46
Reply from 95.217.188.206: bytes=32 time=130ms TTL=46
Reply from 95.217.188.206: bytes=32 time=122ms TTL=46
David Johnson, CDSimple Geek from the '70s
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Commented:
google has turned off icmp replies (ping) from their end

Pinging 216.239.32.15 with 32 bytes of data:
Request timed out.

Ping statistics for 216.239.32.15:
    Packets: Sent = 1, Received = 0, Lost = 1 (100% loss),
Control-C
^C

Author

Commented:

Author

Commented:
Do all NTP server have ping reply turned off?


David Johnson, CDSimple Geek from the '70s
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Commented:
C:\Users\DavidWayneJohnsonCD>tracert 216.239.32.15

Tracing route to time1.google.com [216.239.32.15]
over a maximum of 30 hops:

  1     1 ms     7 ms     6 ms  192.168.0.1
  2    32 ms    23 ms    47 ms  10.66.64.1
  3    13 ms    17 ms    15 ms  10.0.75.169
  4    14 ms    15 ms    16 ms  10.0.18.69
  5     *        *        *     Request timed out.
  6     *        *        *     Request timed out.
  7     *        *        *     Request timed out.
  8     *        *        *     Request timed out.
  9     *        *        *     Request timed out.
 10     *        *        *     Request timed out.
 11     *        *        *     Request timed out.
 12     *        *        *     Request timed out.
 13     *        *        *     Request timed out.
 14     *     ^C
C:\Users\DavidWayneJohnsonCD>

C:\Users\DavidWayneJohnsonCD>tracert pool.ntp.org

Tracing route to pool.ntp.org [216.229.4.69]
over a maximum of 30 hops:

  1    <1 ms     1 ms     1 ms  192.168.0.1
  2    18 ms    17 ms    23 ms  10.66.64.1
  3    17 ms    16 ms    17 ms  10.0.75.173
  4    29 ms    28 ms    29 ms  10.0.18.73
  5    37 ms    10 ms    15 ms  he-as6939.torix.ca [206.108.34.112]
  6    26 ms    25 ms    31 ms  100ge9-2.core2.chi1.he.net [184.105.80.5]
  7    25 ms    32 ms    40 ms  100ge15-2.core1.chi1.he.net [184.104.192.117]
  8    35 ms    42 ms    42 ms  100ge5-2.core1.oma1.he.net [184.105.213.2]
  9    36 ms    41 ms    40 ms  184.105.19.117
 10    43 ms    38 ms    39 ms  core-lnk-1.lnk1.binary.net [216.229.1.146]
 11    42 ms    41 ms    34 ms  triton.ellipse.net [216.229.4.69]

Trace complete.

C:\Users\DavidWayneJohnsonCD>
Edmond HawilaChief Operating Officer
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Commented:
That is quite possible.
NTP uses port 123
Make sure that is open for your device reaching out

Author

Commented:
I have firewall completely turned off for this. I can ping 216.229.4.69 but still showing inaccessible. I tried turning on DNS and using 8.8.8.8 but it was showing same for DNS also.

Author

Commented:
Im going to delete this VM and restart from scratch.
Andrew Hancock (VMware vExpert PRO / EE Fellow)VMware and Virtualization Consultant
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Commented:
but why delete the VM, if your desktop cannot reach the NTP server ?

is 216.229.4.69 <--- NTP server ?

Author

Commented:
i can ping the 216.229.4.69 from my desktop.
Andrew Hancock (VMware vExpert PRO / EE Fellow)VMware and Virtualization Consultant
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Commented:
I'm not getting good time sync from that server - 216.229.4.69
Andrew Hancock (VMware vExpert PRO / EE Fellow)VMware and Virtualization Consultant
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Commented:
could you please confirm the VM interface settings for the networking of the VM ?

Author

Commented:
i am using 192.168.0.50 for the CUCM ip.
Everything else is the same as it was last night when i was able to complete the install.
The NIC is bridged.
My pc ip is 192.168.0.23
The NTP is the same one i used last night that was successful.
David Johnson, CDSimple Geek from the '70s
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Commented:
responding from a ping is not a definite connection item
telnet is though but for only tcp connections.
ntp is udp

You can try using a port scanner or something to scan for open connections.

Author

Commented:
That is way beyond my knowledge.
David FavorFractional CTO
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Commented:
I'll only answer your initial question.

Trying to use yahoo.com for this will just be confusing.

Yahoo rotates random IPV4 + IPV6 addresses.

Also most (not all) Yahoo IPs block ICMP packets, so doing a ping on Yahoo hosts or IPs will sometimes work + sometimes fail.

Use google.com for your testing instead, as all IPV4 + IPV6 Google addresses always respond to ICMP packets.

imac> ping -c 1 google.com
PING google.com (172.217.9.14): 56 data bytes
64 bytes from 172.217.9.14: icmp_seq=0 ttl=116 time=21.827 ms

--- google.com ping statistics ---
1 packets transmitted, 1 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 21.827/21.827/21.827/0.000 ms

imac> ping -c 1 172.217.9.14
PING 172.217.9.14 (172.217.9.14): 56 data bytes
64 bytes from 172.217.9.14: icmp_seq=0 ttl=116 time=22.253 ms

--- 172.217.9.14 ping statistics ---
1 packets transmitted, 1 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 22.253/22.253/22.253/0.000 ms

Open in new window


If either of these ping tests fail, then something on your end is blocking ICMP packet flow, which you'll have to fix.

This will likely be some firewall code running on some device.

You can use a Windows port of the mtr command to determine exactly what host if blocking/dropping ICMP packages by doing this...

If you see 100% packet drop, that's the source of the ICMP problem.

Note: You can only fix this if you own the IP where 100% packet drop occurs...

imac> mtr -r -c 1 google.com
Start: 2020-06-12T22:32:33-0500
HOST: Davids-iMac.local           Loss%   Snt   Last   Avg  Best  Wrst StDev
  1.|-- 192.168.1.1                0.0%     1    0.5   0.5   0.5   0.5   0.0
  2.|-- 10.26.2.83                 0.0%     1    3.8   3.8   3.8   3.8   0.0
  3.|-- ae12.ar01.aus122.googlefi  0.0%     1    2.5   2.5   2.5   2.5   0.0
  4.|-- ???                       100.0     1    0.0   0.0   0.0   0.0   0.0
  5.|-- 23-255-225-179.googlefibe  0.0%     1   21.9  21.9  21.9  21.9   0.0
  6.|-- 23-255-224-63.mci.googlef  0.0%     1   21.4  21.4  21.4  21.4   0.0
  7.|-- 108.170.235.144            0.0%     1   20.5  20.5  20.5  20.5   0.0
  8.|-- 108.170.230.117            0.0%     1   29.1  29.1  29.1  29.1   0.0
  9.|-- dfw06s49-in-f14.1e100.net  0.0%     1   21.4  21.4  21.4  21.4   0.0

Open in new window


Normally routing will... route around packet flow problems... as show above where one host appears non-responsive, so packets route around this host.
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