This is a gotcha but be aware sometimes iptables may be active and loaded by default.
Also make sure you don't just disable firewalld but also stop it otherwise it will still block stuff:
systemctl stop firewalld
If the above is not the issue then it is possible iptables is running and blocking stuff too, so you'll need to stop iptables.
So in addition to opening firewalld or disabling it, you would need to disable iptables........
In Centos 7 tftpd will not work with selinux. Clients will not be able to connect and this is all you'll see in the log (then nothing more):
Sep 18 14:39:15 localhost xinetd: START: tftp pid=4331 from=192.168.1.65
On the client/computer side you will see this:
PXE-M0F: Exiting Intel Boot Agent
Basically the client is being instantly connected and bloc........
Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, root@localhost and inform them of the time the error occurred, and anything you might have done that may have caused the error.
More information about this error may be available in the server error log.
Apache/2.2.15 (CentOS) Server at testdomain.com Port 80........
Essentially a program I was running for mining did not terminate properly with Ctrl+C it is listed as defunct and cannot be killed, kernel is tainted and normal tricks to disable the port are impossible the dev and sys entries for the device cannot be browsed or interacted with in any form without a lockup of the request. The only solution is to reboot due to the kernel taint as far as I can find so far.
[1130246.811056] INFO: task minerd:21861 blocked for more th........
This is a 8TB Seagate external USB 3.0 device apparently newer kernels use a module called "UAS" instead of "USB Storage" which causes issues as a lot of devices are not properly supported in UAS mode by the kernel driver. The solution some say is to disable UAS specifically for your USB device but I'd rather just disable UAS altogether.
Solution blacklist UAS: *do not do this it does not work and just causes your USB 3.0........
This was a surprising bug but I unplugged all drives for an array md127. At first it was just 1 drive and mdadm seemed to notice this. I unplugged the second drive taking the array offline but mdadm did not realize it was offline and still showed a non-existent disk as being part of it. This created problems trying to unmount it or even to stop this array with mdadm freezing.
As for how to fix it I can only think of making sure you are not in a mounted path of........
I created a new partition table on a newly plugged in device and it caused fdisk to hang (even force kill does not work). It also may be a bad drive or some other issue because fdisk -l hangs after the first 2 HDDs (totaly of 8 HDDs on this system):
[1232879.903596] INFO: task fdisk:27176 blocked for more than 120 seconds.
[1232879.903607] Tainted: P&nbs........
Tired of checking iotop and seeing that your drbd partition is using 99.99% of io all the time and finding your drbd device performs slow in general?
This is especially an issue in versions of DRBD in the 8.3 tree in particular one documented case is on "8.3.13" but it likely applies to other devices.
The symptoms are that resyncing is fine and normal but any reasonable amount of activity is very slow and lagged and creates a high server load and con........
This happened while an mdadm array was syncing, all access from writing a new blank file to opening a small .txt file was very slow:
[222117.312078] kjournald starting. Commit interval 5 seconds
[222117.685060] EXT3-fs (md0): using internal journal
[222117.685096] EXT3-fs (md0): mounted filesystem with ordered data mode
[222122.376847] kjournald starting. Commit interval 5 seconds
[222122.602825] EXT3-fs (md2): using internal jour........
ProCurve J4903A Switch 2824
Software revision I.10.77
Copyright (C) 1991-2009 Hewlett-Packard Co. All Rights Reserved.
RESTRICTED RIGHTS LEGEND
Use, duplication, or disclosure by the Government is subject........
What does VPN stand for?
VPN stands for Virtual Private Network and is a secure way of connecting networks and devices.
In the context we're talking about it will usually be a client-server solution and not connecting whole networks or businesses.
The assumption is that most people reading this are trying to secure their internet connection, privacy and hide or change their IPaddress.
Why use a VPN?
There are many........
I used the matching 8.3.13 utilities and it didn't work but strangely the newer 8.3.16 which makes DRBD complain works just fine.
GIT-hash: 83ca112086600faacab2f157bc5a9324f7bd7f77 build by root@sighted, 2012-10-09 12:47:51
0: cs:SyncSource ro:Secondary/Primary ds:UpToDate/Inconsistent A r-----
ns:0 nr:0 dw:0 dr:0 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:5236960
A lot of people become nervous (and understandably so) when checking their auth or security logs, in Centos /var/log/secure and see dozens, hundreds of even thousands of attempted logins to various services, especially SSH.
Of course you could manually block these people/IPs but no one has time to read the logs like that, what if some program or script could do it for you?
This is what denyhosts does for you, it checks the logs and based on a certain number of failed SSH attem........
Could not display "trash:///".
Error: DBus error org.freedesktop.DBus.Error.NoReply: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.
Please select another viewer and try again.
This happened in Ubuntu but only because I was trying to delete millions of files at once and i........
One thing to note about DNS servers and providers is that they aren't always trustworthy, not even if they're Google or your favorite ISP. Any DNS server can compromise your privacy, and they are likely tracking your browsing habits and keeping logs of it. Sometimes it's for Marketing/Research purposes such as Google's GMail service which they admit is scraped/datamined. I would expect nothing less from their DNS service.
The other danger with such widely used and pu........
high IO wait
424 root 39 19 1900 848 552 D 0.0 0.0 0:00.91 updatedb
root 424 0.0 0.0 1900 848 ? DN Mar11 0:00 /usr/bin/updatedb -f sysfs?rootfs?bdev?proc?cpuset?binfmt_misc?debugfs?sockfs?usbfs?pipefs?anon_inodefs?futexfs?tmpfs?inotifyfs?eventp........
Santrex never provided any working server, I believe it was just a dummy management Solus server because the server said it was booted but never connected to the console. I complained to them and eventually the support admitted the server was not working and to wait for 24 hours. I waited for 4-days, after which they sent an e-mail saying my service was being disabled for SPAM ...(when SolusVM shows 0kb of traffic). Th........
These are the only two I've encountered but here is the low-end and note my story is not at all unique.
In my case I was scammed out of money and did not receive any service at all from either company.
Santrex never provided any working server, I believe it was just a dummy management Solus server because the server said it was booted but never connected to the console. I complained to them and eventually the support adm........
I think this will be useful to others because I have a server that kept crashing mysteriously during intense disk usage/RAID checks. It would only crash during the weekly RAID integrity check.
ThenI noticed during a reboot that not all CPUs were being brought up, as a result this actually creates much higher temperatures with the output I got from sensors, just booting the system produced higher than normal temperatures.
You can imagine that a full blown RAID check........
Jan 16 04:02:03 centosbox syslogd 1.4.1: restart.
Jan 16 04:07:34 centosbox kernel: INFO: task updatedb:20771 blocked for more than 300 seconds.
Jan 16 04:07:34 centosbox kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jan 16 04:07:34 centosbox kernel: updatedb D F78BE050 6476 20771 20766&n........
service vz start
Starting OpenVZ: failed to load module vzmon [FAILED]
vzmon: Unknown symbol ve_snmp_proc_init
vzmon: Unknown symbol addrconf_sysctl_free
vzmon: Unknown symbol ve_ndisc_init
vzmon: Unknown symbol addrconf_ifdown
vzmon: Unknown symbol ip6_frag_cleanup
vzmon: Unknown symbol fini_ve_route6