I always forget the exact commands to change the port ssh (or any default service in the case of the selinux bits) runs on. It’s nicely simple though!
Edit /etc/ssh/sshd_config to change the port number:
You can add a second line if you wish to initially leave it running on Port 22 too in case something goes wrong, obviously don’t forget to remove it once the new port is working!
To add port 2022 to port contexts, enter:
# semanage port -a -t ssh_port_t -p tcp 2022
You can verify new settings, enter:
# semanage port -l | grep ssh
ssh_port_t tcp 2022,22
Reload the sshd service to pick up the new config:
#systemctl reload sshd.service
And of course don’t forget to update your firewall to allow the new port through.
So around three months ago (yes, I must do a post on that too) I changed roles at Red Hat and moved from constantly travelling and being on customer sites to working from home. As a result I needed to setup a workspace that I could use day to day.
One thing I’ve always wanted to try is a standing desk. I have back problems, and generally not the best posture, so I thought that would be one way to be able to deal with at least the later, and potentially even the former. The main problem, until recently, is that decent standing desks tend to be very expensive and I didn’t want to needlessly go and spent a lot of extra money for something that would be used for a week and never again. So I decided I would start with a cheap height adjustable desk, which I needed to get anyway due to my height, and then use it as a the basis of a standing desk and then hack it from there. The initial combo I decided on after a lot of looking was the IKEA Galant Height Adjustable Desk at £49 and the IKEA Lack Side table at £8 plus delivery. I figured at less than £100 including delivery if it was terrible I wasn’t wasting a lot of money!
As it turns out it’s been much better than I ever expected it to be. I initially setup the desk to the height I would want when sitting. At a height of six foot three inches I’m not the shortest of people so when sitting I prefer a higher than average desk. Sitting the Lack table on top of the desk by chance also ended up also giving me the perfect standing height. Bonus! A few quid for some foam gym mats plus a decent height adjustable monitor (the most expensive bit by far!) and I was done! Well mostly, I still haven’t decided on a decent keyboard yet.
So how does it look? Well a little bit weird to be honest. How does it work? Better than I ever expected as I find I can happily stand at the desk for a full eight hour working day without too much issue and I’ve even done longer (hello Fedora beta release candidates!!) and my back feels better than it has in a long time! I was also trying to decide on a decent but reasonably priced office chair to buy but now I’m not going to bother. Interestingly IKEA has also just launched the BEKANT sit/stand desk which is reasonably priced and has electric motors for raise/lower. It’s likely I’ll end up getting one of these one day but for the moment my IKEA hack is working pretty well.
The default network config for libvirt is simple and works for most basic use cases but there’s a number of use cases where you need more complex config like Adam outlined for a local bridged config.
I run a number of VMs on a hosted server on the internet and I’ve had on my ToDo list for some time to add a IPSEC site to site VPN but the default network doesn’t make that easy because libvirtd deals with the iptables networking including the NAT automagically.
The network config looks like this:
*-----* 192.168.100.0/24 --| Hyp |-(eth0)- internet (br0) VM net *-----*
Create non routed network bridge
Initially create a basic network bridge and disable STP (spanning tree protocol). Note we don’t bind it with eth0 which is a public internet facing interface.
nmcli con add type bridge ifname br0 nmcli con modify bridge-br0 bridge.stp no
I then edited the /etc/sysconfig/network-scripts/ifcfg-bridge-br0 file and to add IP network config and adjust a few bits to get the following:
DEVICE=br0 STP=no TYPE=Bridge BOOTPROTO=static DEFROUTE=yes IPV4_FAILURE_FATAL=no IPADDR=192.168.100.254 NETMASK=255.255.255.0 IPV6INIT=no IPV6_FAILURE_FATAL=no NAME=bridge-br0 UUID=
Once we’ve done that we can bring the bridge online and check the config looks OK:
ifup br0 nmcli c show nmcli -f bridge con show bridge-br0 ip addr
Now we have a network bridge with an IP address you can now edit any VM configuration and reassign the virtual NICs to the new bridge and adjust the VM network config to the new subnet and assign static IPs to each VM, or configure dhcpd to assign IPs on the br0 interface. Once that’s done you should be able to ping the gateway (192.168.101.254) and have local network connectivity.
Once you’ve moved everything over you can delete the original libvirtd network config.
Outbound NATed networking
Using the traditional iptables.service (firewalld investigation is on my todo list) you can add a basic outbound NAT configuration which restores the last of the missing functionality with the following basic rule set which will NAT by masquerading the br0 network out through the public IP on eth0:
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT iptables -A INPUT -p icmp -j ACCEPT iptables -A INPUT -i lo -j ACCEPT iptables -A INPUT -m state --state NEW -p tcp -m tcp --dport 22 -j ACCEPT iptables -A INPUT -j REJECT --reject-with icmp-host-prohibited iptables -A FORWARD -i eth0 -o br0 -m state --state RELATED,ESTABLISHED -j ACCEPT iptables -A FORWARD -i br0 -o eth0 -j ACCEPT iptables -A FORWARD -j REJECT --reject-with icmp-host-prohibited iptables-save > /etc/sysconfig/iptables systemctl enable iptables.service systemctl start iptables.service
With the network now under complete control of NetworkManager and a IP firewall/NAT configuration under control from a single point it now makes it easier to add things like IPSEC connections and IPv6 configuration both of which are next on the list.
It always annoyed me I couldn’t use my ssh key in a screen session. Every now and again I would try and work it out with google and some trial and error. Eventually with the help of a couple of good bits off the net I worked out what I thought to be the easiest way to achieve it consistently.
Firstly the ssh config bits:
Add the following to your ~/.ssh/config file, creating it if you don’t already have one:
host * ControlMaster auto ControlPath ~/.ssh/master-%r@%h:p
And create the ~/.ssh/rc file:
#!/bin/bash if test "$SSH_AUTH_SOCK" ; then ln -sfv $SSH_AUTH_SOCK ~/.ssh/ssh_auth_sock fi
And make sure they have the correct permissions for ssh:
chmod 600 ~/.ssh/config ~/.ssh/rc
Finally add the following to your ~/.screenrc file:
setenv SSH_AUTH_SOCK $HOME/.ssh/ssh_auth_sock
I’m not sure it’s the best and most effective way but it’s nice and simple and to date it’s been working well for me, I’ve not had issues with it. Any suggestions for improvement feel free to comment.
Disabling SSLv3 in Dovecot is nice and straight forward.
In the /etc/dovecot/conf.d/10-ssl.conf file edit the ssl_cipher_list line to look as below (or adjust to suit your specific requirements):
ssl_cipher_list = ALL:!ADH:!LOW:!SSLv2:!SSLv3:!EXP:!aNULL:+HIGH:+MEDIUM
To test the option to ensure it’ll work you can run the following command before you restart dovecot and the output should look something like below:
$ openssl ciphers -v 'ALL:!ADH:!LOW:!SSLv2:!SSLv3:!EXP:!aNULL:+HIGH:+MEDIUM' ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH Au=RSA Enc=AESGCM(256) Mac=AEAD ECDHE-ECDSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AESGCM(256) Mac=AEAD ECDHE-RSA-AES256-SHA384 TLSv1.2 Kx=ECDH Au=RSA Enc=AES(256) Mac=SHA384 ECDHE-ECDSA-AES256-SHA384 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AES(256) Mac=SHA384 DHE-DSS-AES256-GCM-SHA384 TLSv1.2 Kx=DH Au=DSS Enc=AESGCM(256) Mac=AEAD DHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=DH Au=RSA Enc=AESGCM(256) Mac=AEAD DHE-RSA-AES256-SHA256 TLSv1.2 Kx=DH Au=RSA Enc=AES(256) Mac=SHA256 DHE-DSS-AES256-SHA256 TLSv1.2 Kx=DH Au=DSS Enc=AES(256) Mac=SHA256 ECDH-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH/RSA Au=ECDH Enc=AESGCM(256) Mac=AEAD ECDH-ECDSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH/ECDSA Au=ECDH Enc=AESGCM(256) Mac=AEAD ECDH-RSA-AES256-SHA384 TLSv1.2 Kx=ECDH/RSA Au=ECDH Enc=AES(256) Mac=SHA384 ECDH-ECDSA-AES256-SHA384 TLSv1.2 Kx=ECDH/ECDSA Au=ECDH Enc=AES(256) Mac=SHA384 AES256-GCM-SHA384 TLSv1.2 Kx=RSA Au=RSA Enc=AESGCM(256) Mac=AEAD AES256-SHA256 TLSv1.2 Kx=RSA Au=RSA Enc=AES(256) Mac=SHA256 ECDHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH Au=RSA Enc=AESGCM(128) Mac=AEAD ECDHE-ECDSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AESGCM(128) Mac=AEAD ECDHE-RSA-AES128-SHA256 TLSv1.2 Kx=ECDH Au=RSA Enc=AES(128) Mac=SHA256 ECDHE-ECDSA-AES128-SHA256 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AES(128) Mac=SHA256 DHE-DSS-AES128-GCM-SHA256 TLSv1.2 Kx=DH Au=DSS Enc=AESGCM(128) Mac=AEAD DHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=DH Au=RSA Enc=AESGCM(128) Mac=AEAD DHE-RSA-AES128-SHA256 TLSv1.2 Kx=DH Au=RSA Enc=AES(128) Mac=SHA256 DHE-DSS-AES128-SHA256 TLSv1.2 Kx=DH Au=DSS Enc=AES(128) Mac=SHA256 ECDH-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH/RSA Au=ECDH Enc=AESGCM(128) Mac=AEAD ECDH-ECDSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH/ECDSA Au=ECDH Enc=AESGCM(128) Mac=AEAD ECDH-RSA-AES128-SHA256 TLSv1.2 Kx=ECDH/RSA Au=ECDH Enc=AES(128) Mac=SHA256 ECDH-ECDSA-AES128-SHA256 TLSv1.2 Kx=ECDH/ECDSA Au=ECDH Enc=AES(128) Mac=SHA256 AES128-GCM-SHA256 TLSv1.2 Kx=RSA Au=RSA Enc=AESGCM(128) Mac=AEAD AES128-SHA256 TLSv1.2 Kx=RSA Au=RSA Enc=AES(128) Mac=SHA256
Finally to test it from client side you can run the following command to ensure it’s not enabled. If it’s configured as expected the negotiation should fail and it’ll return you straight to the command prompt:
openssl s_client -connect mail.example.com:993 -ssl3
A question that I’ve had a few times in the last couple of weeks is whether Fedora supports Cute Embedded Nonsense Hacks, also known as u-boot and device tree, on aarch64 (ARM64) platforms?
The answer is YES!, of course, why wouldn’t we?
I know people are well aware of Red Hat’s involvement in the Server Base System Architecture (SBSA) which mandates the use of UEFI 2.4 and ACPI 5.1 bindings and that the Red Hat Partner Early Access Program uses that standard to enable easy booting and support of server platforms running on aarch64 platforms but the fact is that is not Fedora.
Fedora plans to support the SBSA to enable easy use of Fedora on aarch64 server platforms. But we also plan to support the current standard u-boot with device tree boot options. The fact of the matter is that a lot of non server based aarch64 platforms will continue to use these options and so we’ll continue to actively support them. Just like Fedora support Xen when the Fedora derived enterprise product does not. Basically it’s not hard for us to continue these options and with the improved generic distro support in u-boot, which we’ve actively participated in and driven, testing of Cute Embedded Nonsense Hacks on aarch64 should be easy and straight forward.
Of course the support of both SBSA based uEFI/ACPI or u-boot/DTB isn’t perfect on aarch64 yet so if you’ve got access to aarch64 systems on either platforms I would love testing and bug reports. If you’re a vendor that plans on using u-boot/DTB on aarch64 I would ask to ensure that you support the generic distro options because it’ll enable out of the box booting of at least Fedora, Debian and openSUSE to seamlessly just work on your devices.
With 3.17 due momentarily and Fedora 21 been delayed a little we’ll now be bumping the kernel that ships in F-21 GA. So lets have an overview of what improvements and changes are going to be there for ARM.
Overall 3.17 has been relatively boring in terms of shiny new hardware support for ARMv7. We’ve added support for a bunch of new devices through the addition of appropriate device tree bits. Some of the highlights there include a number of AllWinner devices such as the Banana Pi, a number of new FreeScale i.MX6 devices, some of RockChips devices, and the ZYNQ Parallella.
On the aarch64 side there’s been general improvements all over the place. Over all we don’t have any new platforms but there’s improvements to the three we do support (VExprees, APM X-Gene, AMD Seattle) but the VExpress Juno device should work and initial support for the ACPI 5.1 standard and improved uEFI both of which are part of ARM SBSA Server standard.
Along side 3.17, or at least very shortly there after, u-boot 2014.10 or at least a release candidate should land in F-21 as well. This release adds support for a lot of new devices, primarily AllWinner A-10/13/20 categories, as well as the Tegra Jetson K1, a few i.MX6 devices such as the RIoT Board and the newly upstream distro standards for booting. This makes it much easier for us to “just boot” Fedora ARM with a lot more devices making the experience of getting started a lot easier for most people with supported devices.
The combination of u-boot 2014.10 and the 3.17 kernel will be what we head towards Fedora 21 GA with and things are starting to come together nicely.
So having almost recovered from the lack of sleep that is one of the guarantees of conferences in general, but definitely a Fedora one, I thought I would reflect on a few bits. I’m not going to cover all the talks as a lot of people have done that and all the talks are on the Flock 2014 YouTube channel for your viewing pleasure.
As others have mentioned the venue was great, easy to get to and from for transport and the hotel. Huge kudos to the organisers of the event! An event such as this takes a lot of time and energy, and with the dust barely settled the Flock 2015 Bid process is already under way so if you’re interested in hosting 2015 in North America…
My State of ARM and aarch64 in Fedora went well, I enjoyed it and the room was packed with as many people standing as there were sitting There was lots of good questions and interest, both in the talk, and in the hallway in general.
I went to numerous excellent talks, too many to count or remember and I’m looking forward to catching up on a number of talks I missed due to schedule conflicts, via the videos, when I get some spare time. Of course the other major part of the conference is the hall way track. There I had too many conversations to recall and caught up with numerous old friends, met a number of people I’d been dealing with online and had never met in person, and of course met a whole bunch of new friends too! It’s amazing how much can be achieved when talking to someone on the walk between conference rooms!
One of the other major things I enjoyed about Flock this year was the overall positivity of everything about the conference, whether it be people’s general attitude, the presentation titles and the presentations themselves or people in the Litre Pub . And of course being one of our values I have to mention that catching up with so many good friends is always the sugar on top of the cake!
As we slowly meander our way towards the pointy end of the Fedora 21 release, with Alpha speeding up in the rear view mirror, the Fedora ARM team are starting to discuss the best way to deal with the blossoming amount of ARMv7 devices that can and do run out of the box on Fedora.
With our 3.16 kernel containing device tree blobs for 200+ devices, the Fedora 3.17 rawhide kernel already containing 230+, it’s truly impossible to actively test and support all of those devices. So much like previous releases we’ll be focusing on testing a group of “primary devices” with the remainder being considered as secondary. This doesn’t mean they won’t work, it just means they’re not necessarily a testing focus of the regular contributors or they might not be readily available to purchase.
So what makes a device primary? Well there’s a number of considerations we’ve put into the list. Firstly the device has to be widely available and well supported upstream. Some will notice that some of the devices are no longer widely available (yes Panda, Trimslice and Calxeda I’m looking at you!) and I did consider their removal from the list but given a lot of contributors have them I think it’s worthwhile keeping them around for the moment. The primary devices list won’t be release blocking, we don’t block x86 releases for specific single devices, so I don’t believe we should for ARMv7 either.
Astute readers will notice the proposed primary list of around two dozen devices is much larger than the core devices we supported in Fedora 20! YAY! is all I have to say about that
The list is not final, at the moment it’s a suggested list and one open for discussion to some degree and what we’ll be heading from Alpha to Beta with. I fully expect it to be tweaked as we go along, there might be cool new shiny Chromebooks that arrive on the scene and end up working nicely and are hence worth actively supporting (no EXYNOS Chromebooks I’m not looking at you!) and some devices on the list below that end up not making the grade. One thing is for sure the grade includes that they support Cute Embedded Nonsense Hacks ie DeviceTree… there’s no board support here.
- Wandboard (all models/revisions)
- Utilite (all models)
- Cubox-i (all models)
- Hummingboard (all models)
- BeagleBone Black
- Tegra K1 Jetson
- CubieBoard (all models)
- Banana Pi
- PandaBoard (all models)
- Calxeda Highbank/Midway
- VExpress (qemu)
- BeagleBone White
- Beagle xM
- Qualcomm (IFC6410, DragonBoard)
- Various Marvell devices (Mirabox, AX3, CuBox)
- Various Exynos devices
- Other AllWinner devices (as per available u-boot/DT support)
- Gumstix Overo series of devices
- OMAP5 EVM
- STE SnowBall
- AMD Seattle
- APM Mustang
- VExpress (qemu)
So what can a user expect from the primary devices above? Will all the functionality of a device work? Well it depends on the specific device and the associated SoC. For example the AllWinner SoC GPU support is far from upstream so unfortunately there will be no graphical UX for those devices, the Tegra K1 support for the GPU isn’t quite there yet but we’re hoping by GA it will be. Some will be better than others in terms of certain features but for example the AllWinner devices would make good storage devices with their SoC attached SATA and Network, no ugly usb storage/network here, so they are useful to support as a primary device and can easily have feature enablement in the F-21 cycle with a “yum upgrade” to a newer kernel.
We’ll delve deeper into the specifics of each device and the final list closer to beta.
So I’m at Flock in Prague. So far I’ve been to a bunch of interesting talks about Release Engineering, Secondary Architectures, Fedora Workstation, Docker and Infrastructure.
Of course then there’s the hallway track of which I always actively participate and it’s been always fabulous to meet a bunch of people in real life that I’ve been dealing with online on a regular basis, in some cases for years!
I’ll be around for the entire conference and if you’re interested in chatting about secondary architectures (not just ARM), Sugar, Cloud or just about anything else or just to say hi please come and find me!