Introduction to FreeS/WAN

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# Upgrading to FreeS/WAN 2.x

## New! Built in Opportunistic connections

Out of the box, FreeS/WAN 2.x will attempt to encrypt all your IP traffic. It will try to establish IPsec connections for:

- IP traffic from the Linux box on which you have installed FreeS/WAN, and
- outbound IP traffic routed through that Linux box (eg. from a protected subnet).

FreeS/WAN 2.x uses hidden, automatically enabled ipsec.conf connections to do this.

This behaviour is part of our campaign to get Opportunistic Encryption (OE) widespread in the Linux world, so that any two Linux boxes can encrypt to one another without prearrangement. There's one catch, however: you must set up a few DNS records to distribute RSA public keys and (if applicable) IPsec gateway information.

If you start FreeS/WAN before you have set up these DNS records, your connectivity will be slow, and messages relating to the built in connections will clutter your logs. If you are unable to set up DNS for OE, you will wish to disable the hidden connections.

### Upgrading Opportunistic Encryption to 2.01 (or later)

As of FreeS/WAN 2.01, Opportunistic Encryption (OE) uses DNS TXT resource records (RRs) only (rather than TXT with KEY). This change causes a "flag day". Users of FreeS/WAN 2.00 (or earlier) OE who are upgrading may need to post additional resource records.

If you are running initiate-only OE, you must put up a TXT record in any forward domain as per our quickstart instructions. This replaces your old forward KEY.

If you are running full OE, you require no updates. You already have the needed TXT record in the reverse domain. However, to facilitate future features, you may also wish to publish that TXT record in a forward domain as instructed here.

If you are running OE on a gateway (and encrypting on behalf of subnetted boxes) you require no updates. You already have the required TXT record in your gateway's reverse map, and the TXT records for any subnetted boxes require no updating. However, to facilitate future features, you may wish to publish your gateway's TXT record in a forward domain as shown here .

During the transition, you may wish to leave any old KEY records up for some time. They will provide limited backward compatibility.

## New! Policy Groups

We want to make it easy for you to declare security policy as it applies to IPsec connections.

Policy Groups make it simple to say:

- These are the folks I want to talk to in the clear.
- These spammers' domains -- I don't want to talk to them at all.
- To talk to the finance department, I must use IPsec.
- For any other communication, try to encrypt, but it's okay if we can't.

FreeS/WAN then implements these policies, creating OE connections if and when needed. You can use Policy Groups along with connections you explicitly define in ipsec.conf.

For more information, see our Policy Group HOWTO.

## New! Packetdefault Connection

Free/SWAN 2.x ships with the automatically enabled, hidden connection packetdefault. This configures a FreeS/WAN box as an OE gateway for any hosts located behind it. As mentioned above, you must configure some DNS records for OE to work.

As the name implies, this connection functions as a default. If you have more specific connections, such as policy groups which configure your FreeS/WAN box as an OE gateway for a local subnet, these will apply before packetdefault. You can view packetdefault 's specifics in man ipsec.conf .

## FreeS/WAN now disables Reverse Path Filtering

FreeS/WAN often doesn't work with reverse path filtering. At start time, FreeS/WAN now turns rp_filter off, and logs a warning.

FreeS/WAN does not turn it back on again. You can do this yourself with a command like:

       echo 1 > /proc/sys/net/ipv4/conf/eth0/rp_filter

For eth0, substitute the interface which FreeS/WAN was affecting.

## Revised ipsec.conf

### No promise of compatibility

The FreeS/WAN team promised config-file compatibility throughout the 1.x series. That means a 1.5 config file can be directly imported into a fresh 1.99 install with no problems.

With FreeS/WAN 2.x, we've given ourselves permission to make the config file easier to use. The cost: some FreeS/WAN 1.x configurations will not work properly. Many of the new features are, however, backward compatible.

### Most ipsec.conf files will work fine

... so long as you paste this line, with no preceding whitespace, at the top of your config file:

        version 2

### Backward compatibility patch

If the new defaults bite you, use this ipsec.conf fragment to simulate the old default values.

### Details

We've obsoleted various directives which almost no one was using:

        dump
        plutobackgroundload
        no_eroute_pass
        lifetime
        rekeystart
        rekeytries

For most of these, there is some other way to elicit the desired behaviour. See this post.

We've made some settings, which almost everyone was using, defaults. For example:

        interfaces=%defaultroute
        plutoload=%search
        plutostart=%search
        uniqueids=yes

We've also changed some default values to help with OE and Policy Groups:

        authby=rsasig   ## not secret!!!
        leftrsasigkey=%dnsondemand ## looks up missing keys in DNS when needed.
        rightrsasigkey=%dnsondemand

Of course, you can still override any defaults by explictly declaring something else in your connection.

A post with a list of many ipsec.conf changes.
Current ipsec.conf manual.

### Upgrading from 1.x RPMs to 2.x RPMs

Note: When upgrading from 1-series to 2-series RPMs, rpm -U will not work.

You must instead erase the 1.x RPMs, then install the 2.x set:

        rpm -e freeswan

        rpm -e freeswan-module

On erasing, your old ipsec.conf should be moved to ipsec.conf.rpmsave. Keep this. You will probably want to copy your existing connections to the end of your new 2.x file.

Install the RPMs suitable for your kernel version, such as:

        rpm -ivh freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

        rpm -ivh freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

Or, to splice the files:

        cat /etc/ipsec.conf /etc/ipsec.conf.rpmsave > /etc/ipsec.conf.tmp
        mv /etc/ipsec.conf.tmp /etc/ipsec.conf

Then, remove the redundant conn %default and config setup sections. Unless you have done any special configuring here, you'll likely want to remove the 1.x versions. Remove conn OEself, if present.

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