Michael Tremer

Feature Spotlight: On-Demand IPsec VPNs
by Michael Tremer, May 1

Although this is not really rocket science, I find this feature exciting. VPNs that switch on when you need them and switch off when they are idle. It is as simple as that. The IPsec stack inside IPFire is under constant development and improvement. With almost every single update, we introduced some minor new feature or added ciphers, integrity algorithms or simply just fixed bugs.

Today, I would like to highlight this one feature though: On-Demand VPNs

It works in that way, that strongSwan, the software that is negotiating IPsec connections is installing a trigger in the kernel. When ever a packet is sent from a client on the local network to a destination on the other side of the VPN, it will hit that trigger which then causes strongSwan to try to establish the connection.

strongSwan is doing all sorts of protocol negotiations, but as soon as a VPN connection is established, the kernel is doing the heavy lifting; i.e. encrypting and decryption as well as routing packets. It is really fast doing that and given the right hardware, IPFire is able to route 10G VPN connections with solid encryption of course!

During the establishment of a VPN connection, the client will continue trying the other end of VPN. Some retransmissions might happen if opening up the VPN takes a little bit longer. But as soon as it is up, the connection is ready for use as usual.

Has no packet been transferred over the VPN for 15 minutes, the connection will automatically be shut down. That means that the system can save some resources since it does not constantly need to re-negotiate the IPsec Security Association and send keep-alive packets. On some weaker systems that will save some resources.

IPsec is however quite lightweight so that this is not really a problem to keep up a tunnel. But it adds up quickly if you have a number of them. That is one of the main motivations to build this in the first place. Some other reasons are that strongSwan tries a little bit harder to establish the tunnel if there is traffic (because of the triggers) which helps to keep up flaky connections, too.

How to?

To enable all this goodness, there is not much to do. Just go to the “Advanced Settings” section of your IPsec net-to-net connection and select “On-Demand” as “Start Action”. That is all there is to do. The other (and default) option is too keep up the connection at all times.

The status will be shown on the web user interface as “ON-DEMAND” when the connection is idle. If it is up, it will show as “CONNECTED” as it did before.

Michael Tremer

IPFire 2.19 - Core Update 110 is available for testing
by Michael Tremer, April 5

Hello Community,

it is once again time to give the next Core Update a good test before it is rolled out to everyone. We included some exciting features in this one as well as updates of many system packages and many bug and security fixes.

On-Demand IPsec VPNs

IPFire used to keep IPsec VPNs up all the time. This wastes resources if a connection is not used very often for example for a daily backup only.

Core Update 110 allows to configure IPsec VPNs in an On-Demand mode which will establish the connection as soon as it is needed and will close it after 15 minutes of inactivity to save resources.

This is especially handy for people who have a large number of IPsec net-to-net connections on either weak hardware or connections that are not required all the time like maintenance or backup connections, etc.

Performance Enhancements for DNS

unbound, the DNS resolver working inside IPFire, has been tuned to allow more concurrent queries and assigned more memory to keep a larger DNS cache.

Especially in large networks or when a burst of DNS queries needs to be handled, there is a notable increase of performance.


Updated Packages

apcupsd 3.14.14, bind 9.11.0-P3, cairo 1.14.8, conntrack-tools 1.4.4, fontconfig 2.12.1, freetype 2.7.1, lm_sensors 3.4.0, nettle 3.3, ntp 4.2.8p10, openssh 7.4p1 – for PCI compliance, pixman 0.34.0, squid 3.5.25, unbound 1.6.1, wget 1.19.1


avahi 0.6.32, cups 2.2.2 & cups-filter, ffmpeg 3.2.4, ghostscript 9.20, mc 4.8.19, motion 4.0.1, mpd 0.20.6, tcpdump 4.9.0

New Packages

As always, we would like to ask all users to participate in testing which will highly improve the quality of this update.

Please report any bugs to our bug tracker and provide any feedback on our development mailing list.

Michael Tremer

IPFire 2.19 - Core Update 109 is available for testing
by Michael Tremer, February 4

The next Core Update with number 109 has been released for testing. It comes with a number of package updates which include security fixes and bug fixes all across the place.

DNS Fixes

The DNS proxy which is working inside IPFire has been updated to unbound 1.6.0 which brings various bug fixes. Therefore, QNAME minimisation and hardening below NX domains have been re-activated.

At start time, IPFire now also checks if a router in front of IPFire drops DNS responses which are longer than a certain threshold (some Cisco devices do this to “harden” DNS). If this is detected, the EDNS buffer size if reduced which makes unbound fall back to TCP for larger responses. This might slow down DNS slightly, but keeps it working after all in those misconfigured environments.



As always, we would like to ask all users to participate in testing which will highly improve the quality of this update.

Please report any bugs to our bug tracker and provide any feedback on our development mailing list.

Michael Tremer

Public Service Announcement: A reminder on writing bug reports
by Michael Tremer, December 16


because many struggle with this quite often, I would like to re-port a brief text from this blog from 2013 about how to write a good bug report:

How to write a good bug report?

We developers rely on these and we need good technical information to be able to investigate and not to burn your and our time. So as a personal reminder from me, please keep these guidelines in mind when you encounter a problem next time and help us to solve it.

Have a good weekend,

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