<div dir="ltr">Saw similar on an install of Centos 6.4, just figured it was the datacenters rolled version, as it went away when I booted into the OpenVZ kernel I installed on the server. Never saw it again after that.</div>
<div class="gmail_extra"><br><br><div class="gmail_quote">On Tue, Apr 8, 2014 at 2:32 PM, Shannon Gernyi <span dir="ltr"><<a href="mailto:shannon.gernyi@xsv.com.au" target="_blank">shannon.gernyi@xsv.com.au</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hey all,<br>
<br>
I have a few boxen running CentOS 6.5 in a very vanilla install.<br>
<br>
I ran into some weird behaviour that I couldn't get to the bottom of, and whilst a reboot "fixed" it, I'm not going to be able to sleep at night without asking the question, so riddle me this:<br>
<br>
Box A is on a private network:<br>
<br>
eth0 <a href="http://172.27.3.111/24" target="_blank">172.27.3.111/24</a><br>
<br>
I'm have a requirement to broadcast on eth0, however, the box isn't sending said broadcast packets to the ethernet broadcast mac - it's sending out ARP requests for 172.27.3.255 instead.<br>
<br>
12:49:44.129501 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:49:45.129494 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:49:46.129494 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:49:48.132491 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:49:49.132488 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:49:50.132491 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:49:52.135503 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:49:53.135486 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:49:54.135513 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:49:56.139497 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:49:57.139491 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:49:58.139494 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:50:00.131503 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:50:01.131490 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:50:02.131495 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:50:04.134495 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:50:05.134487 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:50:06.134490 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:50:08.137499 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:50:09.137488 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
<br>
eth0 is definitely configured correctly regarding network/mask:<br>
<br>
eth0 Link encap:Ethernet HWaddr REMOVED<br>
inet addr:172.27.3.111 Bcast:172.27.3.255 Mask:255.255.255.0<br>
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1<br>
RX packets:227898706 errors:0 dropped:0 overruns:0 frame:0<br>
TX packets:219816363 errors:0 dropped:0 overruns:0 carrier:0<br>
collisions:0 txqueuelen:1000<br>
RX bytes:59578359175 (55.4 GiB) TX bytes:145429518480 (135.4 GiB)<br>
Interrupt:245<br>
<br>
arp output confirms the above dump:<br>
<br>
arp -n<br>
Address HWtype HWaddress Flags Mask Iface<br>
172.27.3.255 (incomplete) eth0<br>
<br>
<br>
And finally, manually adding the IP to the arp table with a destination of ethernet broadcast (ie, where the frames should be directed anyway) made things work:<br>
<br>
arp -s 172.27.3.255 ff:ff:ff:ff:ff:ff<br>
<br>
<br>
12:56:30.232505 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:56:31.232506 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:56:32.232496 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:56:34.235510 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:56:35.235505 ARP, Request who-has 172.27.3.255 tell 172.27.3.111, length 28<br>
12:56:36.042743 IP 172.27.3.111.53957 > 172.27.3.255.ha-cluster: UDP, length 225<br>
12:56:36.236321 IP 172.27.3.111.53957 > 172.27.3.255.ha-cluster: UDP, length 246<br>
12:56:36.236353 IP 172.27.3.111.53957 > 172.27.3.255.ha-cluster: UDP, length 225<br>
12:56:38.238098 IP 172.27.3.111.53957 > 172.27.3.255.ha-cluster: UDP, length 225<br>
<br>
<br>
Now, I can't go back and debug further, but if anyone has seen this or similar behaviour before - please share possible explanations. It's doing my head in!<br>
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</blockquote></div><br></div>