Setup external USB disk as NTFS volume on Raspbian

I intend to use an external 2.5″ USB disk formatted as NTFS volume on my Raspberry Pi. Since its rather larger (5TB) I don’t want to use MBR but GPT instead. Here’s a short list of commands I’ve used to setup the disk.

Start by identifying the connected disk:

> lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda           8:0    0  4.6T  0 disk
└─sda1        8:1    0  4.6T  0 part
mmcblk0     179:0    0 14.9G  0 disk
├─mmcblk0p1 179:1    0  1.5G  0 part
├─mmcblk0p2 179:2    0    1K  0 part
├─mmcblk0p5 179:5    0   32M  0 part
├─mmcblk0p6 179:6    0   69M  0 part /boot
├─mmcblk0p7 179:7    0  8.2G  0 part /
├─mmcblk0p8 179:8    0  512M  0 part
└─mmcblk0p9 179:9    0  4.5G  0 part

My disk is sda.

I now usually used fdisk as a partitioning tool. However, there’s a tool I can highly recommend. Its called parted and can be installed using:

sudo apt-get install parted

Since I’ll want to use ntfs as file system, I’ll need to install the ntfs drivers:

sudo apt-get install ntfs-3g

Now create a new GPT partition table:

> sudo parted /dev/sda mklabel gpt
Warning: The existing disk label on /dev/sda will be destroyed and all data on this disk will be lost. Do you want to continue?
Yes/No? yes
Information: You may need to update /etc/fstab.

Now create a new partition with ntfs. I’ll use all of the available space, so its from 0 to 100%:

> sudo parted -a opt /dev/sda mkpart primary ntfs 0% 100%
Information: You may need to update /etc/fstab.

Now format the disk in quick format with ntfs. It will label the partition as “SynoBackups”:

> sudo mkfs.ntfs -L SynoBackups -Q /dev/sda1
Cluster size has been automatically set to 4096 bytes.
Creating NTFS volume structures.
mkntfs completed successfully. Have a nice day.

This label is very helpful in identifying the partition, even when it is connected to a different USB port. Using a device like sda might point to a different drive, so its better to use the label. This is one of the big advantages of using gpt in comparison to mbr.

Let’s see the label in action:

sudo lsblk --fs
NAME        FSTYPE LABEL       UUID                                 MOUNTPOINT
sda
└─sda1      ntfs   SynoBackups 4EE12D1B5321171F
mmcblk0
├─mmcblk0p1 vfat   RECOVERY    525E-19E4
├─mmcblk0p2
├─mmcblk0p5 ext4   SETTINGS    ceb0ae64-8675-406b-8eed-2244c26814c8
├─mmcblk0p6 vfat   boot        8454-E385                            /boot
├─mmcblk0p7 ext4   root0       65678398-7f53-48ec-8452-c277500fb4e8 /
├─mmcblk0p8 vfat               AC0D-3FB1
└─mmcblk0p9 ext4               ff645116-fe34-43bf-a580-b89fa963085d

Note that there’s also a more specific id, the UUID. We will use this UUID later when we configure a default mount point in /etc/fstab.

Now we’ll try to mount the new partition. Create a folder to mount the partition and mount it manually:

sudo mkdir /mnt/backups
sudo mount -o defaults /dev/sda1 /mnt/backups

Verify that the disk is mounted and try to write some stuff to it:

> df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/root       8.0G  2.7G  4.9G  36% /
devtmpfs        457M     0  457M   0% /dev
tmpfs           462M     0  462M   0% /dev/shm
tmpfs           462M  6.2M  455M   2% /run
tmpfs           5.0M  4.0K  5.0M   1% /run/lock
tmpfs           462M     0  462M   0% /sys/fs/cgroup
/dev/mmcblk0p6   68M   23M   46M  33% /boot
/dev/sda1       4.6T  210M  4.6T   1% /mnt/backups

> sudo lsblk --fs
NAME        FSTYPE LABEL       UUID                                 MOUNTPOINT
sda
└─sda1      ntfs   SynoBackups 4EE12D1B5321171F                     /mnt/backups
mmcblk0
├─mmcblk0p1 vfat   RECOVERY    525E-19E4
├─mmcblk0p2
├─mmcblk0p5 ext4   SETTINGS    ceb0ae64-8675-406b-8eed-2244c26814c8
├─mmcblk0p6 vfat   boot        8454-E385                            /boot
├─mmcblk0p7 ext4   root0       65678398-7f53-48ec-8452-c277500fb4e8 /
├─mmcblk0p8 vfat               AC0D-3FB1
└─mmcblk0p9 ext4               ff645116-fe34-43bf-a580-b89fa963085d

> echo "success" | sudo tee /mnt/backups/file
success
> cat /mnt/backups/file
success
> rm /mnt/backups/file
> sudo umount /mnt/backups

Now we’ll add the partition to /etc/fstab so that it can be mounted automatically:

UUID=4EE12D1B5321171F   /mnt/backups    ntfs    defaults        0       2

See that I’m now using the UUID instead of /dev/sda to mount the ntfs volume to /mnt/backups. We can test the new setting:

> sudo mount -a
> df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/root       8.0G  2.7G  4.9G  36% /
devtmpfs        457M     0  457M   0% /dev
tmpfs           462M     0  462M   0% /dev/shm
tmpfs           462M  6.2M  455M   2% /run
tmpfs           5.0M  4.0K  5.0M   1% /run/lock
tmpfs           462M     0  462M   0% /sys/fs/cgroup
/dev/mmcblk0p6   68M   23M   46M  33% /boot
/dev/sda1       4.6T  210M  4.6T   1% /mnt/backups

I think this is a really nice change in mounting the volumes and will create a more stable configuration, regardless which USB port you’ve used to connect your drive.

Block SSH connections by origin of IP address

If you’re exposing services to the internet, you’ll notice a lot of connection attempts. To block those bots and scripts trying to login to your machine, you should use fail2ban.

However, you can also limit the range of allowed origins of the IP addresses. The company MaxMind provides a database of IP addresses and their origin contries. You can configure your machine in such a way that only certain country codes are allowed.

Start by installing the geoip client and database by using this apt command:

sudo apt-get install geoip-bin geoip-database

This database is updated automatically, when you’ve got your machine configured for auto updates.

The next step is to save this script to your machine in /usr/local//usr/local/bin/ipfilter.sh:

Edit the script to your needs, e.g. by limiting the number of allowed countries. Now make this script executable:

chmod +x /usr/local/bin/ipfilter.sh

It is time to test it. Try the command with a known IP in America and one from a local network or known IP from the allowed countries:

> /usr/local/bin/ipfilter.sh
Usage:  ipfilter.sh <ip>
> /usr/local/bin/ipfilter.sh 8.8.8.8
> echo $?
1
> /usr/local/bin/ipfilter.sh 192.168.1.1
> echo $?
0

Notice the different exit codes of the script. If the IP is from a country that is allowed or if it is from a local network, it will exit with 0, otherwise 1. We can use this script now to configure a filter for sshd in the /etc/hosts.allow and /etc/hosts.deny files.

Add to /etc/hosts.allow:

sshd: ALL: spawn /usr/local/bin/ipfilter.sh %a

Add to /etc/hosts.deny:

sshd: ALL

Please note the trailing newline. If this is the last entry in the hosts file, you’ll need to add a newline. Otherwise the role won’t be active.

Do a reboot of your machine and try to connect. You should still be able to connect 😉 Otherwise you’ll need to revert this changes locally, since you’ve successfully blocked yourself from accessing that machine.

This should reduce the amount of blocked SSH connections attempts significantly, if configured to a smaller selection of countries.

Email notification for fail2ban events

So I’ve configured my fail2ban installation and I’m also able to send emails. But wouldn’t it be awesome if I’ll get notified via email about any fail2ban event?

We start with editing the /etc/fail2ban/jail.local file. Look for the destemail and action parameters and change them accordingly:

mta = sendmail
destemail = recipient@domain.name
senderemail = sender@domain.name
action = %(action_mwl)s

The action can be one of these, whereby I’ve chosen action_mwl:

  • action_: ban only the IP
  • action_mw: ban the IP and send email with whois information about the banned IP
  • action_mwl: ban the IP and send email with whois information about the banned IP and add relevant log lines to the email
  • action_cf_mwl: notify Cloudfare about the offending IP, ban the IP and send email with whois information about the banned IP

Do a restart of fail2ban:

sudo systemctl restart fail2ban

You’ll receive a lot of emails from fail2ban. This also includes any starts and stops of fail2ban as well as the ban notifications. You can limit this behavior by adding following content to the file /etc/fail2ban/action.d/mail-buffered.local:

[Definition]

# Option:  actionstart
# Notes.:  command executed once at the start of Fail2Ban.
# Values:  CMD
#
actionstart =

# Option:  actionstop
# Notes.:  command executed once at the end of Fail2Ban
# Values:  CMD
#
actionstop =

Now copy this file a few times with different file names:

sudo cp /etc/fail2ban/action.d/mail-buffered.local /etc/fail2ban/action.d/mail.local
sudo cp /etc/fail2ban/action.d/mail-buffered.local /etc/fail2ban/action.d/mail-whois-lines.local
sudo cp /etc/fail2ban/action.d/mail-buffered.local /etc/fail2ban/action.d/mail-whois.local
sudo cp /etc/fail2ban/action.d/mail-buffered.local /etc/fail2ban/action.d/sendmail-buffered.local
sudo cp /etc/fail2ban/action.d/mail-buffered.local /etc/fail2ban/action.d/sendmail-common.local

Do a restart of fail2ban:

sudo systemctl restart fail2ban

You should now only receive emails for ban events.

Protect SSH services with fail2ban

If you’ll open SSH on a server to the open internet, you’ll notice a lot of bots trying to login. You certainly should setup certificate based login, but banning offending IPs is also an important security measure.

I’ve installed fail2ban on my Raspbian installations and want to explain the installation and configuration. Its quite easy and the benefits are huge!

sudo apt-get install fail2ban

Create a copy of the original configuration file so that it won’t be overwritten by any updates:

sudo cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local

Search for a block for [default]. You should set:

bantime = 10m
findtime = 10m
maxretry = 5

These are the general settings. The settings for sshd should be a little bit stricter. Search a block for [sshd]. You should set:

enabled = true
maxretry = 3

You can enable and start fail2ban now using systemctl:

sudo systemctl enable fail2ban
sudo systemctl start fail2ban

Verify its up and running:

sudo systemctl status fail2ban.service
sudo fail2ban-client status
sudo fail2ban-client status sshd

If you end up being locked out, you can unlog an offending IP address using this command:

sudo fail2ban-client set sshd unbanip <offenders IP>

Banned connections will be dropped immediately by the firewall and should be visible with a “connection refused”.