Joining a Samba server to an Active Directory Domain fails

# net ads join member -U Administrator
Failed to join domain: Failed to set machine spn: Constraint violation
Do you have sufficient permissions to create machine accounts?

Simple cause, found after hours and hours:

In the smb.conf were some netbios alias definitions, of which one was already defined in some other hosts SPN.

Either remove the spn from the other host, delete this (in my case) obsolete, old host or remove this alias from smb.conf.

Just lost an hour or so for a simple task: Configuring sendmail to use smart_host with authentication on CentOS7.

TL;DR: "AUTH=client, available mechanisms do not fulfill requirements" just needed a "yum install cyrus-sasl-plain"

I started with configuring sendmail to use smart_host with auth credentials:

1. Add authorization informations to /etc/mail/authinfo file:

AuthInfo:your-smart-host.tld "U:USERNAME" "P:PASSWORD"

2. Add following lines to /etc/mail/sendmail.mc:

define(`SMART_HOST', `your-smart-host.tld')  
FEATURE(`authinfo')

3. Update sendmail.cf and access.db files:

# cd /etc/mail
# make
# systemctl sendmail restart

But maillog showed temporary failures AUTH=client, available mechanisms do not fulfill requirements.

I checked the servers supported authentication methods with:

# echo -e "ehlo me\nquit" | openssl s_client -starttls smtp -crlf -quiet -connect your-smart-host.tld:25 2>/dev/null | grep AUTH
250-AUTH LOGIN PLAIN

Kept debugging, logging and searching google. Found a forum post where someone solved it by installing cyrus-sasl*.

Well it turned out that only cyrus-sasl-plain was missing and the solution was a simple

yum install cyrus-sasl-plain

Since there was no sysresccd with current ZoL 0.6.5.2 modules available I looked around for an alternative.
At http://voidmain.is-a-geek.net/redhat/fe ... cking.html I found a recipe for a custom Fedora-Live-CD.

Follow these steps to create a ZFS-Live-CD:
(I used a Fedora-Live-Xfce-x86_64-21-5.iso I had at hand on my Fedora 21 WS)

Start with a new working directory

mkdir Fedora-Live
cd Fedora-Live

Unpack the Fedora-Live ISO

mkdir iso
mount -o ro,loop Fedora-Live.iso iso
mkdir source
cp -a iso/* source
umount iso

Extract the embedded ext-FS

unsquashfs source/LiveOS/squashfs.img

Extend the ext-FS. Alternatively remove unneded packages inside the chroot. See below.

truncate -s4G squashfs-root/LiveOS/ext3fs.img
resize2fs squashfs-root/LiveOS/ext3fs.img

Mount the ext-FS to chroot into it

mkdir ext3fs
mount -o loop squashfs-root/LiveOS/ext3fs.img ext3fs
mount -o bind /proc ext3fs/proc
mount -o bind /dev ext3fs/dev
mount -o bind /sys ext3fs/sys
cp /etc/resolv.conf ext3fs/etc/
chroot ext3fs

I did remove a bunch of unneeded packages and unused leave packages instead of extending the fs.
One could of course remove even more packages (or single files) to make the system fit on a 512MB stick.

yum erase -y xf* *font* web* *theme* xorg* *gtk* gst* mesa* selinux* trans* tele* pulse* esp*
while package-cleanup --quiet --leaves --exclude-bin | xargs yum remove -y; do true ; done

The ZFS install is straight forward.

yum install -y http://archive.zfsonlinux.org/fedora/zfs-release$(rpm -E %dist).noarch.rpm
yum install -y zfs kernel-devel-$(rpm -q kernel --qf '%{VERSION}-%{RELEASE}.%{ARCH}\n')
dkms status

Exit from the chroot

exit

Copy your current locale settings

cp /etc/vconsole.conf ext3fs/etc/
cp /etc/locale.conf ext3fs/etc/
cp -P /etc/localtime ext3fs/etc/

Instruct getty to autologin root

vi ext3fs/lib/systemd/system/getty@.service

  ExecStart=-/sbin/agetty --autologin root --noclear %I $TERM

Clean the unused space for better compression

dd if=/dev/zero bs=128k of=ext3fs/zero
sync
rm -f ext3fs/zero

Unmount the ext-FS and make the squashfs

umount ext3fs/sys
umount ext3fs/proc
umount ext3fs/dev
umount ext3fs
mksquashfs squashfs-root source/LiveOS/squashfs.img -noappend

Update the isolinux configuration with a new cd label, add selinux=0 and remove quiet and rhgb

vi source/isolinux/isolinux.cfg

   CDLABEL=ZFS-Live selinux=0

vi source/EFI/BOOT/grub.cfg

   LABEL=ZFS-Live selinux=0

Make the new ISO

mkisofs -o ZFS-Live.iso -J -r -hide-rr-moved -hide-joliet-trans-tbl -V ZFS-Live -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table source

Burn to CD or copy to usb flash

livecd-iso-to-disk --format --label ZFS-Live ZFS-Live.iso /dev/sd?-of-your-usb-disk

Done.

After building the iPad-serial-to-Cisco-console-management-cable I decided that using minicom was a bit unhandy.

So i hacked together a bit of python with pySerial and added some lines of HTML and Javascript:

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There are a couple of pages on the net, describing how to build a serial cable for jailbroken iDevices, e.g. iPhone serial port or Console to routers using the iPad.

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