The file ipsec.secrets holds a table of secrets.
These secrets are used by the strongSwan Internet Key Exchange (IKE) daemons
pluto (IKEv1) and charon (IKEv2) to authenticate other hosts.
It is vital that these secrets be protected. The file should be owned
by the super-user,
and its permissions should be set to block all access by others.
The file is a sequence of entries and include directives.
Here is an example.
# /etc/ipsec.secrets - strongSwan IPsec secrets file
192.168.0.1 %any : PSK "v+NkxY9LLZvwj4qCC2o/gGrWDF2d21jL"
: RSA moonKey.pem
firstname.lastname@example.org : EAP "x3.dEhgN"
carol : XAUTH "4iChxLT3"
dave : XAUTH "ryftzG4A"
# get secrets from other files
Each entry in the file is a list of optional ID selectors, followed by a secret.
The two parts are separated by a colon (:) that is surrounded
by whitespace. If no ID selectors are specified the line must start with a
A selector is an IP address, a Fully Qualified Domain Name, user@FQDN,
%any or %any6 (other kinds may come).
Matching IDs with selectors is fairly straightforward: they have to be
equal. In the case of a Road Warrior connection, if an equal
match is not found for the Peers ID, and it is in the form of an IP
address, a selector of %any will match the peers IP address if IPV4
and %any6 will match a the peers IP address if IPV6.
Currently, the obsolete notation 0.0.0.0 may be used in place of
In IKEv1 an additional complexity
arises in the case of authentication by preshared secret: the
responder will need to look up the secret before the Peers ID payload has
been decoded, so the ID used will be the IP address.
To authenticate a connection between two hosts, the entry that most
specifically matches the host and peer IDs is used. An entry with no
selectors will match any host and peer. More specifically, an entry with one
selector will match a host and peer if the selector matches the hosts ID (the
peer isnt considered). Still more specifically, an entry with multiple
selectors will match a host and peer if the host ID and peer ID each match one
of the selectors. If the key is for an asymmetric authentication technique
(i.e. a public key system such as RSA), an entry with multiple selectors will
match a host and peer even if only the host ID matches a selector (it is
presumed that the selectors are all identities of the host).
It is acceptable for two entries to be the best match as
long as they agree about the secret or private key.
Authentication by preshared secret requires that both systems find the
identical secret (the secret is not actually transmitted by the IKE
protocol). If both the host and peer appear in the selector list, the
same entry will be suitable for both systems so verbatim copying
between systems can be used. This naturally extends to larger groups
sharing the same secret. Thus multiple-selector entries are best for PSK
Authentication by public key systems such as RSA requires that each host
have its own private key. A host could reasonably use a different private keys
for different interfaces and for different peers. But it would not
be normal to share entries between systems. Thus thus no-selector and
one-selector forms of entry often make sense for public key authentication.
The key part of an entry must start with a token indicating the kind of
key. The following types of secrets are currently supported:
Details on each type of secret are given below.
defines a pre-shared key
defines an RSA private key
defines an ECDSA private key
defines a PKCS#12 container
defines EAP credentials
defines NTLM credentials
defines XAUTH credentials
defines a smartcard PIN
Whitespace at the end of a line is ignored. At the start of a line or
after whitespace, # and the following text up to the end of the
line is treated as a comment.
An include directive causes the contents of the named file to be processed
before continuing with the current file. The filename is subject to
globbing as in sh(1), so every file with a matching name
is processed. Includes may be nested to a modest
depth (10, currently). If the filename doesnt start with a /, the
directory containing the current file is prepended to the name. The
include directive is a line that starts with the word include,
followed by whitespace, followed by the filename (which must not contain