• SSH error cannot Forward or Listen "bind: Cannot assign requested address"


    debug1: Local connections to LOCALHOST:18006 forwarded to remote address 192.168.1.93:8006 debug1: Local forwarding listening on 127.0.0.1 port 18006. debug1: channel 0: new [port listener] debug1: Local forwarding listening on ::1 port 18006. bind: Cannot assign requested address What we are seeing is that we can't listen on an IPV6 address of ::1. We need to tell SSH to stop using IPV6 so we'll edit ssh_config to take care of this issue........
  • How To Edit Linux Based NM Network Manager Connection Settings Without GUI


    Just find the relevant file in /etc/NetworkManager/system-connections sudo vi /etc/NetworkManager/system-connections/Wired connection 1 [802-3-ethernet] duplex=full mac-address=00:00:00:FE:FE:FE [connection] id=Wired connection 1 type=802-3-ethernet timestamp=1532403341 [ipv6] method=ignore [ipv4] method=manual........
  • Linux Disable IPV6 Centos / Debian / Mint Howto


    Set this in /etc/sysctl.conf net.ipv6.conf.all.disable_ipv6 = 1 #apply the settings sudo sysctl -p ........
  • VMWare Vsphere VCSA Graphical Install Creates json


    yes it does create its own json ============================================ cat /tmp/vcsaUiInstaller/ovftool-20180809-175238948-20180809-175603497.log |grep -i json 2018-08-09T17:56:04.238-07:00 verbose OVFTool[30966] [Originator@6876 sub=Default] Manifest file entry: SHA1(VMware-vCenter-Server-Appliance-6.7.0.12000-8832884_OVF10-file1.json) = 1deb658c724767697587d5909c4051c01813e6a1 --> ........
  • VMWare 6.7 VCSA VSphere ESXi Management SSO Install Guide on Linux using the CLI


    #mount the VCSA DVD mount /dev/sr0 /mnt/cd #alternatively you could mount the iso directly mount -o loop vcsa.iso /your/mount/path #for this purpose we are using the CLI installer on Linux cd /mnt/cd/vcsa-cli-installer/lin64 #no it's not going to be that easy you can't just run vcsa-deploy like that you need to use a template or configured .json file ./vcsa-deploy Usage: vcsa-deploy [-h] [--version] [--supported-deploymen........
  • vino server error cannot login


    10/07/2018 03:05:14 PM [IPv4] Got connection from client10.10.25.1 10/07/2018 03:05:14 PM other clients: 10/07/2018 03:05:14 PM Client Protocol Version 3.7 10/07/2018 03:05:14 PM Advertising security type 18 10/07/2018 03:05:14 PM Client returned security type 18 10/07/2018 03:05:14 PM TLS Handshake failed: Could not negotiate a supported cipher suite. 10/07/2018 03:05:14 PM Client10.10.25.1 gone 10/07/2018 03:05:14 PM Statistics:........
  • OpenVPN cannot ping remote IP routing loop issue after connecting


    Sometimes if you have a very basic configuration OpenVPN on the client side for some reason sends all traffic to the OpenVPN server IP through the tun0 which is of course impossible and creates a block or routing loop. This is because you need to use your normal ISP/LANgateway to hit the OpenVPN server if it is remote/offsite as is usually the case. So if you are connected to the OpenVPN through say a tun0 device and your routing is set to connect to the OpenVPN&nbs........
  • possible SYN flooding on ctid 42131, port 80. Sending cookies. - Solution


    The Linux Kernel interpretated a very high volume of real traffic as a DDOS attack so it basically ends up blocking your web server. possible SYN flooding on ctid 42131, port 80. Sending cookies. Simple fix edit sysctl values for max_syn_backlog sysctl -w net.ipv4.tcp_max_syn_backlog=5000 To make them permanent edit /etc/sysctl.conf echo "net.ipv4.tcp_........
  • DRBD Split-brain solution


    Uh oh [17925926.174277] block drbd0: Handshake successful: Agreed network protocol version 96 [17925926.174325] block drbd0: conn( WFConnection -> WFReportParams ) [17925926.174342] block drbd0: Starting asender thread (from drbd0_receiver [1682]) [17925926.174432] block drbd0: data-integrity-alg: [17925926.174581] block drbd0: drbd_sync_handshake: [17925926.174586] block drbd0: self 2AAE66AF9252D6DB:2815BF........
  • cPanel Install Error kernel ipv6 module support solution


    2017-01-12 14:25:36 529 (ERROR): The installer was unable to verify that your kernel supports IPv6. 2017-01-12 14:25:36 530 (ERROR): The message received when trying to create an IPv6 socket was Address already in use 2017-01-12 14:25:36 531 (ERROR): Please ensure that the ipv6 module is enabled and loaded in your kernel. 2017-01-12 14:25:36 532 (FATAL): Exiting... Solution This happened........
  • iptables how to forward localhost port to remote public IP


    iptables -t nat -A OUTPUT -m addrtype --src-type LOCAL --dst-type LOCAL -p tcp --dport 3306 -j DNAT --to-destination ip.ip.ip.ip iptables -t nat -A POSTROUTING -m addrtype --src-type LOCAL --dst-type UNICAST -j MASQUERADE sysctl -w net.ipv4.conf.all.route_localnet=1 Make sure you substitute "ip.ip.ip.ip" for your real public IP and also the "--dport 3306" for the port you want to forward. Finally run the sysctl command and........
  • OpenVZ Solution CPT ERR: c02fa000,73 :CPT: lock fd is closed incorrectly: 1 and vps-net_add ERROR: Unable to add route ip route add 192.168.5.2 dev venet0


    The only solution after trying many suggestions was to simply restart the "vz" service (definitely not preferable). Even doing an ifdown and ifup for venet0 did not help. ifup venet0 Bringing up interface venet0: Configuring interface venet0: net.ipv4.conf.venet0.send_redirects = 0 RTNETLINK answers: Network is down Some errors from log: CPT ERR: d2dc60........
  • DRBD Slow Performance - 99.99 % [jbd2/drbd0-8] highiowait solution


    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........
  • Openvz kernel: [10186978.064405] TCP: time wait bucket table overflow (CT3)


    kernel: [10186978.064405] TCP: time wait bucket table overflow (CT3) Varying opinions are out there but in general it seems like the most common culprit is a lack of privvmpages, with a modern OpenVZ system the best way is to set privvmpages as equal to what your RAM is and this has resolved the messages on another system. If it's truly a TCP issue you can adjust the following parameters:........
  • OpenVZ Install Guide Again / Quick Setup


    yum -y install wget wget -P /etc/yum.repos.d/ http://ftp.openvz.org/openvz.repo rpm --import http://ftp.openvz.org/RPM-GPG-Key-OpenVZ yum -y install vzkernel vzctl #enable ip_forward sed -i s/'net.ipv4.ip_forward = 0'/'net.ipv4.ip_forward = 1'/g /etc/sysctl.conf #all interfaces should not send redirects echo "net.ipv4.conf.default.send_redirects = 1" >> /etc/sysctl.conf echo "net.ipv4.co........
  • Linux disable firmware prevents NIC/Ethernet from working phy0 -> rt2x00lib_request_firmware: Error - Failed to request Firmware.


    [ 17.208336] tg3 0000:08:00.0: eth0: Link is up at 1000 Mbps, full duplex [ 17.210194] tg3 0000:08:00.0: eth0: Flow control is on for TX and on for RX [ 76.000065] phy0 -> rt2x00lib_request_firmware: Error - Failed to request Firmware. [ 76.002332] ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready [ 86.736004] eth0: no IPv6 routers present [ 148.960038] phy0 -> rt2x00lib_request_fi........
  • VPN Account Buyers Guide and General Info


    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........
  • Apache SNI is not needed what is the issue?


    Iread this article and still don't understand the issue. If I understand correctly the client negotiates after the first SSLconnection and then gets the correct hostname and thus correct certificate. http://wiki.apache.org/httpd/NameBasedSSLVHostsWithSNI To their credit I know I'm not using SNIbecuase Iget this message in the Apache log :) [warn] Init: You should not use name-based virtual hosts in conjunction with SSL!! B........
  • ip_conntrack: table full, dropping packet. solution for Linux RHEL/Centos/Debian


    ip_conntrack: table full, dropping packet. A lot of clients I've seen have this issue, it really seems the default level is way too small. Once this connection tracking table becomes full then packets get dropped which is obviously a bad thing. One thing to be mindful of though is that 350 bytes of memory are used per entry so there is some justification for not keeping it too high. However, if you have multiple servers running or high traffic daemons........
  • vino crashed/stopped working, restart vino manually without rebooting


    The normal solution would be as follows: export DISPLAY=:0.0 /usr/lib/vino/vino-server & But what happens if that doesn't work? I haven't been able to find much documentation about how to find the list of displays and how their numbering works in Xorg. Sometimes you'll get this error when trying to restart vino: Cannot open display: For some reason my display is not on 0.0........
  • How to view UDP and other protocol connections?


    netstat is weak and can't show udp connections and most other protocols, use "ss" which is what netstat should have been: The "-u" switch stands for udp, here's a list of other options: Usage: ss [ OPTIONS ] ss [ OPTIONS ] [ FILTER ] -h, --help this message -V, --version output ver........
  • connect: No buffer space available Oct 18 12:21:03 vps kernel: printk: 177 messages suppressed. Oct 18 12:21:03 vps kernel: Neighbour table overflow.


    ping test.com connect: No buffer space available /var/log/messages Oct 18 12:21:03 vps kernel: printk: 177 messages suppressed. Oct 18 12:21:03 vps kernel: Neighbour table overflow. Solution in /etc/sysctl.conf: net.ipv4.neigh.default.gc_thresh1 = 4096 net.ipv4.neigh.default.gc_thresh2 = 8192 net.ipv4.neigh.default.gc_thresh3 = 8192 net.ipv4.neigh.default.base_reachab........
  • Openvz Error Starting OpenVZ: failed to load module vzmon [FAILED]


    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........
  • 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 vzm


    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 ........
  • Openvz Quick Install for CentOS 5 Tutorial


    cd /etc/yum.repos.d wget http://download.openvz.org/openvz.repo rpm --import http://download.openvz.org/RPM-GPG-Key-OpenVZ yum install ovz-kernel-PAE Now remember to set /etc/sysctl.conf to "net.ipv4.ip_forward = 1" You can apply the change immediately by running sysctl -w net.ipv4.ip_forward = 1 but remember that you still have to set sysctl.conf sysctl -p will load and apply any changes to s........
  • Realtek r8169 1gbit/1000mbit NIC/Ethernet Goes Down/Halts on Large File Transfer/Heavy Network Usage


    This is obviously a bug in the r8169 kernel module and it seems to affect a lot of people. I upgraded to the latest kernel and hope this won't happen anymore, as it is a very serious error. This is especially serious for those who are running servers with this chipset, who can afford for the NIC to randomly go off-line for no apparent reason? [655548.189113] type=1505 audit(1277067560.902:5): operation="profile_load" name="/usr/bin/freshclam&q........
  • FUSE/Curlftpfs mount ftp account as drive partition in Linux


    This is a great way to use your ftp server space, for example on your web hosting account (althoughI believe many hosts don't allow storage like this), but if you have a VPS/Dedicated Server etc.., this would be perfect. Imagine how easy it is to work with an ftp account that you can just mount as a normal partition or directory in Linux, it would be great for backups etc.. Name curlftpfs - mount a ftp host as a local directory Synopsis........
  • OCFS2 crash


    When trying to even cd or ls the mounted OCFS2 partition it crashes. Ithink this is a combination of VMWare Server's problem and the way I mounted and symlinked to it. More than anything this shows the problem and lack of forsight with VMWare, but also that OCFS2 is easily crashed if you do strange things. Output of /var/log/messages for OCFS2 Apr 10 15:57:45 localhost kernel: [84331.691258] Modules linked in: vmnet vmci vmmon ocfs2_stac........
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