The most important is the admin entry as without that the user will not be able to run sudo and hence perform any system administration. Of course if you want to add a different user and don’t want to give them admin access then you don’t need to make any updates to the /etc/group file.
type
exit
to logout and now login under the new username to check that it is working correctly.
By default the shell for the new user is the bourne shell. The bash shell is an improvement on that allowing the user of the arrow keys on the command line and autocompletion.
To set the default shell for you new account (when logged in under that account) use:
chsh -s /bin/bash
You could now remove the pi username if it is no longer required.
userdel pi
Although at the time of writing the current image had an error in the passwd file – which will need to be fixed using the pwck command first.
This is just the initial stages in making the Pi more secure. There are other aspects to Linux security including making sure that appropriate security fixes are applied as they become available (eg. apt-get update).
操作系统性能优化Performance tuning is something that you would normally leave until later, but in the case of the Raspberry Pi there is an single option that can be done to improve performance for servers. By configuring it here we can let it get picked up by the reboot later saving us from having to reboot the server.
The Raspberry Pi has 256Mb (or 512Mb for later versions) of RAM. This RAM is however shared between the graphics and main system memory. By default 64Mb is allocated to graphics. This is overkill if you don’t plan to run the graphical interface (or rarely) as in the case of a server. To reduce the amount of memory available for graphics to 32MB enter the following command.
sudo cp /boot/arm224_start.elf /boot/start.elf, or use sudo raspi-config to do this using the config menu
(you can restore the previous configuration sudo cp /boot/arm192_start.elf /boot/start.elf )
This requires a reboot to take effect, but we will be rebooting later, so there is no need to reboot at this point.
配置网络The next step is to give the Raspberry Pi an static IP address. This is a little more complex as it depends upon your own setup and what router you have on how to achieve this.
By default the Raspberry Pi will request a dynamic IP address which is issued by your router as required. This however may change in future which would make it hard to connect to the webserver. Instead we provide it with an address that doesn’t change such as 192.168.1.4.
Note that this address can be used on the local network, but not on the Internet – later we’ll look at providing access through your router / firewall from the Internet.
First find out what DHCP address has been allocated by using the ifconfig command – see the extract below
... eth0 Link encap:Ethernet HWaddr b8:27:eb:8a:71:a0 inet addr:192.168.1.110 Bcast:192.168.1.255 Mask:255.255.255.0 ...This is saying that the ethernet port 0 – has an IP address of 192.168.1.110
You will also need to find out what address your router is, using the route command
$ route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface default 192.168.1.1 0.0.0.0 UG 0 0 0 eth0 192.168.1.0 * 255.255.255.0 U 0 0 0 eth0This shows that the router IP address (Gateway) is 192.168.1.1 and all traffic is sent via that router.
At this point you will also need to check on what address range is being issued by the router. This depends upon the individual router. In my case I have a Belkin Wireless Routerwhich can be reached by pointing a web browser to the IP address of the router 192.168.1.1
The LAN settings are shown below:
In this case the local network has valid addresses from 192.168.1.1 to 192.168.1.254. The router is at address 192.168.1.1 and any DHCP requests will be given entries between 192.168.1.100 and 192.168.1.150 (you can change the range of the DHCP addresses if required). I have used 192.168.1.4 for this server.
To change to static IP address
cd /etc/network sudo nano interfacesreplace the line “iface eth0 inet dhcp” with
iface eth0 inet static address 192.168.1.4 netmask 255.255.255.0 gateway 192.168.1.1You should also take a look at the file /etc/resolv.conf
and check it has a nameserver entry (probably pointing at your default gateway)
nameserver 192.168.1.1
Alternatively you could point directly at your ISPs DNS servers rather.
Whilst you can dynamically reload the network interface I suggest a reboot at this stage to make sure that the configuration is correct.
sudo reboot