Yup, my guess is that someone has plugged in another device into your
network and that device has a ip address 192.168.41.4 statically
assigned.
Or someone has reconfigured a device and set that address by accident.
I had a UPS do this to me once.
A quick lookup on the https://macvendors.com/ shows the offending mac
address belongs to a device from Dell Inc. That may help you track
down the offender.
Hope this helps.
On Thu, Feb 23, 2017 at 8:27 AM, Rommel Rodriguez Toirac
<rommelrt@xxxxxxxx> wrote:
> El 21 de febrero de 2017 7:00:03 GMT-05:00, centos-request@xxxxxxxxxx escribió:
>>Send CentOS mailing list submissions to
>> centos@xxxxxxxxxx
>>
>>
>>From: Kahlil Hodgson <kahlil.hodgson@dp.exchange>
>>To: CentOS mailing list <centos@xxxxxxxxxx>
>>Subject: Re: Network conections problems
>
>>
>>First guess is that you may have two devices on the network with the
>>same ip address.
>>
>>Next time this happens, try doing
>>
>>1. 'arp -n' from a machine other than the db server
>>2. ping the other machine from the db server, then
>>3. 'arp -n' from the other machine
>>
>>Compare the outputs of the two invocations of arp. If the outputs show
>>different MAC addresses for 192.168.41.4 then you have two different
>>devices with the same IP address.
>>
>>
> I resolve the problem of network conection loose, but still a dude of how it happend and how it can be fixe.
> When I check with arping the MAC of sever change, for example
>
> rommel@p6:~$ arping 192.168.41.4
> ARPING 192.168.41.4 from 192.168.41.6 enp3s0
> Unicast reply from 192.168.41.4 [00:1D:09:FF:44:4B] 0.653ms
> Unicast reply from 192.168.41.4 [6C:92:BF:26:C7:03] 0.683ms
> Unicast reply from 192.168.41.4 [6C:92:BF:26:C7:03] 0.622ms
> Unicast reply from 192.168.41.4 [6C:92:BF:26:C7:03] 0.631ms
> ^CSent 3 probes (1 broadcast(s))
> Received 4 response(s)
>
> The first answer is with a MAC diferent to the others one.
> But when I arping from the server inseft look the MAC associate to de IP address:
>
> [root@pgtm ] arping 192.168.41.4 -I eth1
> ARPING 192.168.41.4 from 192.168.41.4 eth1
> Unicast reply from 192.168.41.4 [00:1D:09:FF:44:4B] 0.658ms
> Unicast reply from 192.168.41.4 [00:1D:09:FF:44:4B] 0.654ms
> Unicast reply from 192.168.41.4 [00:1D:09:FF:44:4B] 0.654ms
> Unicast reply from 192.168.41.4 [00:1D:09:FF:44:4B] 0.662ms
> Unicast reply from 192.168.41.4 [00:1D:09:FF:44:4B] 0.655ms
> Sent 5 probes (1 broadcast(s))
> Received 5 response(s)
>
> Looking in the config of network device I can not find the MAC 00:1D:09:FF:44:4B
>
> [root@pgtm ] ifconfig
> eth0 Link encap:Ethernet HWaddr 6C:92:BF:26:C7:02
> UP BROADCAST MULTICAST MTU:1500 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
> Memory:c7220000-c723ffff
>
> eth1 Link encap:Ethernet HWaddr 6C:92:BF:26:C7:03
> inet addr:192.168.41.4 Bcast:192.168.41.255 Mask:255.255.255.0
> inet6 addr: fe80::6e92:bfff:fe26:c703/64 Scope:Link
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:95819 errors:0 dropped:0 overruns:0 frame:0
> TX packets:1924 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:11728605 (11.1 MiB) TX bytes:263674 (257.4 KiB)
> Memory:c7200000-c721ffff
>
> eth2 Link encap:Ethernet HWaddr 00:E0:ED:33:4E:9C
> UP BROADCAST MULTICAST MTU:1500 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
> Memory:c7120000-c713ffff
>
> eth3 Link encap:Ethernet HWaddr 00:E0:ED:33:4E:9D
> UP BROADCAST MULTICAST MTU:1500 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
> Memory:c7100000-c711ffff
>
> lo Link encap:Local Loopback
> inet addr:127.0.0.1 Mask:255.0.0.0
> inet6 addr: ::1/128 Scope:Host
> UP LOOPBACK RUNNING MTU:65536 Metric:1
> RX packets:249609 errors:0 dropped:0 overruns:0 frame:0
> TX packets:249609 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:0
> RX bytes:52090343 (49.6 MiB) TX bytes:52090343 (49.6 MiB)
>
> The solution was another IP address to this network device and then everything work fine.
> Why this happend? How I can erase the link beteewn MAC 00:1D:09:FF:44:4B and IP 192.168.41.4? Where can be stored this link?
> Right now in the network is not assignet the IP address 192.168.41.4 to no one device (printserver, switch, router, workstation or server) and still whe I make arping have the answer:
>
> rommel@p6:~$ arping 192.168.41.4
> ARPING 192.168.41.4 from 192.168.41.6 enp3s0
> Unicast reply from 192.168.41.4 [00:1D:09:FF:44:4B] 0.631ms
> Unicast reply from 192.168.41.4 [00:1D:09:FF:44:4B] 0.623ms
> Unicast reply from 192.168.41.4 [00:1D:09:FF:44:4B] 0.623ms
> Unicast reply from 192.168.41.4 [00:1D:09:FF:44:4B] 0.691ms
> ^CSent 4 probes (1 broadcast(s))
> Received 4 response(s)
>
> arping to the new server IP address look like this (this is the MAC of eth0, where a plug the network cable):
>
> rommel@p6:~$ arping 192.168.41.7
> ARPING 192.168.41.7 from 192.168.41.6 enp3s0
> Unicast reply from 192.168.41.7 [6C:92:BF:26:C7:02] 0.580ms
> Unicast reply from 192.168.41.7 [6C:92:BF:26:C7:02] 0.607ms
> Unicast reply from 192.168.41.7 [6C:92:BF:26:C7:02] 0.613ms
> Unicast reply from 192.168.41.7 [6C:92:BF:26:C7:02] 0.594ms
> ^CSent 4 probes (1 broadcast(s))
> Received 4 response(s)
>
>
>
> Rommel Rodriguez Toirac
> rommelrt@xxxxxxxx
> _______________________________________________
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> CentOS@xxxxxxxxxx
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--
Kahlil (Kal) Hodgson GPG: C9A02289
Chief Technology Officer (m) +61 (0) 4 2573 0382
Direct Pricing Exchange Pty Ltd
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"All parts should go together without forcing. You must remember that
the parts you are reassembling were disassembled by you. Therefore,
if you can't get them together again, there must be a reason. By all
means, do not use a hammer." -- IBM maintenance manual, 1925
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