add the following lines to /etc/sysctl.conf
# IPv6 net.ipv6.conf.all.disable_ipv6 = 1 net.ipv6.conf.default.disable_ipv6 = 1 net.ipv6.conf.lo.disable_ipv6 = 1
… and reboot.
Or simply reload the settings:
sysctl -p
2019 update:
sysctl.conf still works, but it won’t be processed during boot.
Therefor recent Ubuntu’s need an extra grub parameter ipv6.disable=1. Like so:
GRUB_CMDLINE_LINUX_DEFAULT="splash quiet ipv6.disable=1" GRUB_CMDLINE_LINUX="ipv6.disable=1"
Quick reference:
Too bad the hp software doesn’t support 3.x kernels, so you need to fool it a little.
setarch i686 --uname-2.6 hpacucli controller all show config
In my case i’m migrating from a Kerio Mailserver that is presenting all the folders as a subfolder of inbox, hence the
--sep1 . --prefix1 inbox
Always start the commands with the “–dry” option to do a dry-run (test-run) first!
To migrate the inbox and all subfolders:
imapsync --syncinternaldates --useheader 'Message-Id' --buffersize 8192000 --nosyncacls --host1 oldhost.domain.com --user1 [email protected] --passfile1 passfile1.txt --ssl1 --host2 imap.gmail.com --user2 [email protected] --passfile2 passfile2.txt --ssl2 --authmech2 LOGIN --sep1 . --sep2 . --prefix1 inbox --folderrec INBOX
Sent items need a little bit of translation. “Sent Items” will be translated to “[Gmail]\Verzonden berichten” (Dutch language).
imapsync --syncinternaldates --useheader 'Message-Id' --buffersize 8192000 --nosyncacls --host1 oldhost.domain.com --user1 [email protected] --passfile1 passfile1.txt --ssl1 --host2 imap.gmail.com --user2 [email protected] --passfile2 passfile2.txt --ssl2 --authmech2 LOGIN --sep1 . --prefix1 inbox --folder "Sent Items" --regextrans2 's/Sent Items/\[Gmail\]\/Verzonden berichten/'
If you want to rsync data from/to a remote server with ssh, you could do something like this:
rsync -av [email protected]:/backup/* /storage/monday/
But what if ssh listens on port 2222?
rsync -av --rsh='ssh -p2222' [email protected]:/backup/* /storage/monday/
But what if you need sudo permissions?
Server-side configuration (/etc/sudoers)
#sudo access for myusername running rsync backup myusername ALL=NOPASSWD:/usr/bin/rsync
Client-side:
rsync -av --rsh='ssh -p2222' --rsync-path="sudo rsync" [email protected]:/backup/* /storage/monday/ .
And in case you want to include multiple directories:
rsync -av --rsh='ssh -p2222' --rsync-path="sudo rsync" [email protected]:{/backup,/root,/etc} /storage/monday/
To translate the timestamps in your dmesg into human readable timestamps, use the following perl script:
#!/usr/bin/perl
$uptime = `cat /proc/uptime | awk '{print $1}';`;
$boot = time() - $uptime;
chomp $boot;
while (<STDIN>) {
if ($_ =~ /^\[([\s\d\.]+)\]/) {
$time_offset = $1;
}
$real_time = sprintf scalar localtime($boot + $time_offset);
$_ =~ s/\[[\s\d\.]+\]/\[$real_time\]/;
print $_;
}
e.g.
[ 9.815650] 3w-9xxx: scsi2: ERROR: (0x03:0x0101): Invalid command opcode:opcode=0x85.
will be translated into
[Wed Mar 16 16:02:32 2011] 3w-9xxx: scsi2: ERROR: (0x03:0x0101): Invalid command opcode:opcode=0x85.
Syntax:
dmesg | perl /root/print_time_offset.pl
If you attach an extra harddisk to your virtual machine and you don’t want to reboot, all you need to do is rescan your scsi bus.
First determine how many scsi adapters your system has:
# ls /sys/class/scsi_host host0
Then order the rescan command to the adapter:
# echo "- - -" > /sys/class/scsi_host/host0/scan
Check your dmesg or /proc/partitions!
I needed to make a backup of an old server. So i booted an Ubuntu live cd. Then:
cat /proc/partitions
But I wasn’t able to mount certain partitions. It appeared to be lvm volumes.
To mount them, you’ll need the lvm2 package first.
sudo -s apt-get update apt-get install lvm2
Then find the volumes.
vgchange -a y 3 logical volume(s) in volume group "VolGroup00" now active
Now look in your device mapper:
ls /dev/mapper/
.. and do whatever you like with it. In my case:
mkdir /mnt/vol00 mkdir /mnt/vol01 mkdir /mnt/vol02 mount /dev/mapper/VolGroup00-LogVol00 /mnt/vol00 mount /dev/mapper/VolGroup00-LogVol01 /mnt/vol01 /dev/mapper/VolGroup00-LogVol01 looks like swapspace - not mounted root@ubuntu:~# mount /dev/mapper/VolGroup00-LogVol02 /mnt/vol02 apt-get install smbfs mkdir /mnt/targetserver/ smbmount //10.2.18.224/software /mnt/targetserver/ mkdir /mnt/targetserver/serverbackup/ cd /mnt rsync -av vol00 vol02 /mnt/targetserver/
Where as Windows has many many cloning tools (e.g. Ghost), for linux cloning isn’t quite common.
Yesterday i needed to migrate an installation to another server. First make sure that you compile all the things you need in your current kernel.
With a Iinux live cd I created a backup of my boot partition (/dev/sda1) to a file on a usb disk (mounted as /backup)
dd if=/dev/sda1 of=/backup/sda1.dd
Then i wanted to restore it to another machine with a different partition size.
Here’s how:
mount -o loop -t ext3 /backup/sda1.dd /backupsda1
mount /dev/sda1 /mnt
cd /backupsda1 rsync -av * /mnt/
mount -t proc none /mnt/proc mount -o bind /dev /mnt/dev
chroot /mnt
grub-install /dev/sda
That’s it!
edit:
if your previous installation has an older version of grub, you might need to create your filesystem with a smaller inode size, otherwise grub won’t function correctly:
mkfs.ext3 -I 128 /dev/sda1
This week i was copying large amounts of data to a Maxtor USB disk using the midnight commander. While the midnight commander was gathering information about the amounts of data to be processed (taking at least 20 minutes or more), the usb disk was going into standby mode.
By the time it was ready and wanted to start copying data, i got all kinds of i/o errors on /dev/sdb (the usb disk).
So i did a filesystem check on the usb disk and started over again. The same happened.
Then it occured to me: the usb disk was going to standby mode. It will come back alive whenever the OS wants to read or write data, but it takes too long resulting in i/o errors.
This command prevents the disk from going to standby mode:
sdparm --clear STANDBY -6 /dev/sdb
edit:
Today i played around with some usb disks that don’t support the command above, so i had to dig further.
Seems like i missed this option in my (custom compiled) kernel: ” [*] USB selective suspend/resume and wakeup “. This is actually the real fix.
When using linux as a router you also might want to forwards some ports.
This should do the trick (it will when using my script from the other post):
iptables -A PREROUTING -t nat -i eth1 -p tcp --dport 80 -j DNAT --to 192.168.1.50:80 iptables -A INPUT -p tcp -m state --state NEW --dport 80 -i eth1 -j ACCEPT
But more generally it might be necessary to add an extra line first to allow traffic to your nic connected to the internet at all:
iptables -A FORWARD -i eth1 -o eth0 -p tcp --dport 80 -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT iptables -A PREROUTING -t nat -i eth1 -p tcp --dport 80 -j DNAT --to 192.168.1.50:80 iptables -A INPUT -p tcp -m state --state NEW --dport 80 -i eth1 -j ACCEPT
Back in the days in our student house we used an old pentium II machine to share our internet access. Hardware routers were much more expensive those days.
A simple script to make a NAT router (replace INTERNET= and LOCALNET= if you have other devices).
Place the script in /etc/network/if-up.d/ (at least with debian) and call it natrouter.sh. Make sure you chmod +x natrouter.sh.
#!/bin/sh INTERNET=eth0 LOCALNET=eth1 PATH=/usr/sbin:/sbin:/bin:/usr/bin # delete all existing rules iptables -F iptables -t nat -F iptables -t mangle -F iptables -X # Always accept traffic on individual interfaces iptables -A INPUT -i lo,$INTERNET,$LOCALNET -j ACCEPT # Allow established connections back to the LAN iptables -A FORWARD -i $INTERNET -o $LOCALNET -m state --state ESTABLISHED,RELATED -j ACCEPT # Allow outgoing connections from the LAN to INTERNET iptables -A FORWARD -i $LOCALNET -o $INTERNET -j ACCEPT # Masquerade iptables -t nat -A POSTROUTING -o $INTERNET -j MASQUERADE # Don't forward from the outside to the inside iptables -A FORWARD -i $INTERNET -o $LOCALNET -j REJECT # Enable routing echo 1 > /proc/sys/net/ipv4/ip_forward