sslserver(1)                General Commands Manual               sslserver(1)



NAME
       sslserver - accept TLS connections and setup SSL CTX

SYNOPSIS
       sslserver [ opts ] host port prog

DESCRIPTION
       opts  is  a  series  of getopt-style options, host is a host name or IP
       address, port is a TCP port, and prog is one or more arguments specify‐
       ing a program to run for each accepted connection.

       The server's address is given by host and port.

BINDINGS
       sslserver  will be attached to the primary IP address of host while the
       host name is fed through qualification using dns_ip6_qualify.  If  host
       is given as dotted decimal IPv4 or compactified IPv6 address, sslserver
       will bind uniquely to those.  In order to bind sslserver to a LLU  IPv6
       address  (ie. fe80::a:b:c) additionally the interface name -Iifname has
       to be provided.

       Note: The kernel might use temporary changing SLAAC addresses.

       sslserver can be instructed to be multi-homing capable while binding to
       all available IP addresses. Now host is given as 0.0.0.0 or ::.

       Further,  sslserver  can  be forced to provide dual-stack capabilities,
       thus allowing IPv4 and IPv6 clients to attach to the same instance once
       host equals ':0' as pseudo IP address.

       port  may  be  a  numeric  port  number  or a port name.  If port is 0,
       sslserver will choose a free port.

SERVING
       sslserver listens for connections from  TCP  clients.   Typically,  for
       each connection, it runs prog, with file descriptor 0 reading from, and
       file descriptor 1 writing to a child process ssl.  If however sslserver
       is called with the option -n, it communcates with prog on mutually cho‐
       sen, arbitrary file descriptors.  prog needs to support  the  UCSPI-TLS
       API.   The  ssl  process attempts an SSL accept via the network.  If it
       succeeds, it translates data between prog and the  network,  performing
       any   necessary  SSL  encoding  and  decoding.   Before  running  prog,
       sslserver reads and sets certain environment variables.

       sslserver exits when it receives SIGTERM.

OPTIONS
       General Options:

       -q     Quiet. Do not print error messages.

       -Q     (Default.) Print error messages.

       -v     Verbose. Print error and status messages.

       -V     Print additional verbose SSL connection  informations  (protocol
              and cipher).


       Connection options:

       -1     After  preparing  to  receive  connections, print the local port
              number to standard output.

       -4     Use IPv4 sockets for connections.

       -6     Use IPv6 connections. This will set PROTO to TCP6 and  put  IPv6
              addresses in TCP6LOCALIP and TCP6REMOTEIP.

       -c n   Do  not  handle  more than n simultaneous connections.  If there
              are n simultaneous connections copies  of  prog  running,  defer
              acceptance  of a new connection until one copy finishes.  n must
              be a positive integer. The default value is 40.

       -x cdb Follow the rules compiled into cdb by tcprules.  These rules may
              specify  setting  environment variables or rejecting connections
              from bad sources.  You can rerun tcprules to  change  the  rules
              while sslserver is running.

       -X     With  -x cdb, allow connections even if cdb does not exist. Nor‐
              mally sslserver will drop the connection if cdb does not exist.

       -B banner
              Write banner to the network immediately after each  SSL  connec‐
              tion is made. The banner is subject to SSL encryption.

       -g gid Switch  group  ID to gid after preparing to receive connections.
              gid must be a positive integer.

       -u uid Switch user ID to uid after preparing  to  receive  connections.
              uid must be a positive integer.

       -U     Same  as  -g  $GID  -u $UID. Typically, $GID and $UID are set by
              envuidgid.

       -I ifname
              Bind to the network interface ifname ("eth0" on Linux, for exam‐
              ple).   This  is  only  defined  and  needed for IPv6 link-local
              addresses.

       -b n   Allow a backlog of approximately n pending connections.

       -o     Leave IP options alone. If the client is sending  packets  along
              an IP source route, send packets back along the same route.

       -O     (Default.) Kill IP options.  A client can still use source rout‐
              ing to connect and to send data, but packets will be  sent  back
              along the default route.

       -d     Delay  sending  data  for  a  fraction  of a second whenever the
              remote host is responding slowly. This is currently the default,
              but  it may not be in the future; if you want it, set it explic‐
              itly.

       -D     Never delay sending data; enable TCP_NODELAY.

       -t n   Give up on the $SSLREMOTEINFO connection attempt  after  n  sec‐
              onds. The default value is: 26.

       -T n   Give  up  on  the  SSL  connection  attempt after n seconds. The
              default value is: 26.

       -w n   Give up on a connection or program after waiting n  seconds  for
              read or write. The default value is: 3600.


       SSL and TLS connection options:

       -n     Delay setup of SSL environment until a STARTTLS/STLS command has
              been issued by the client.

       -N     (Default.) Setup the SSL environment immediately.

       -s     Store client and server certificate information in the  environ‐
              ment, a la mod_ssl.

       -S     (Default.)  Do  not store client and server certificate informa‐
              tion in the environment.


       X509 certificate and encryption options:

       -3     Read a null-terminated key password from file descriptor 3.

       -m     (Mail.) Require valid client certificates, but don't  check  for
              matching FQDN.

       -z     (Host.)  Require  valid  client  certificates and match FQDN (if
              given) against SAN/DN.

       -Z     (Default.) Do not require client certificates.


       Data-gathering options:

       -h     (Default.) Look up the remote host name in DNS to set the  envi‐
              ronment variable $SSLREMOTEHOST.  In this case, additionally the
              CN/SAN in the X509 certificate can  be  checked,  provided,  the
              option -z is set.

       -H     Do  not look up the remote host name in DNS; remove the environ‐
              ment variable $SSLREMOTEHOST.  To avoid loops, you must use this
              option for servers on TCP port 53.

       -p     Paranoid.  After looking up the remote host name in DNS, look up
              the IP addresses in DNS for that host name, and remove the envi‐
              ronment  variable  $SSLREMOTEHOST if none of the addresses match
              the client's IP address.

       -P     (Default.) Not paranoid.

       -l localname
              Do not look up the local host name in DNS; use localname for the
              environment  variable $SSLLOCALHOST.  A common choice for local‐
              name is 0. To avoid loops, you must use this option for  servers
              on TCP port 53.

       -r     Attempt to obtain $SSLREMOTEINFO from the remote host.

       -R     (Default.)  Do  not  attempt  to  obtain $SSLREMOTEINFO from the
              remote host.  To avoid loops,  you  must  use  this  option  for
              servers on TCP ports 53 and 113.

       -e     Set  protocol  environment  a  la  tcpserver .  Set $TCPLOCALIP,
              $TCPLOCALPORT,  $TCPLOCALHOST,   $TCPREMOTEIP,   $TCPREMOTEPORT,
              $TCPREMOTEHOST,  and  $TCPREMOTEINFO as well as for IPv6 connec‐
              tions additionally $TCP6LOCALIP, $TCP6LOCALPORT,  $TCP6LOCALHOST
              together  with  $TCP6REMOTEIP,  $TCP6REMOTEPORT, $TCP6RMEOTEHOST
              and  $TCP6INTERFACE  from  the  current  $SSL  environment  (see
              below).

       -E     (Default.) Do not set any tcpserver environment variables.

DNS RESOLVER SETTINGS
       Use  $DNSCACHEIP  to set the DNS resolver IP dynamically irrespectively
       from the settings in /etc/resolv.conf.   If  the  environment  variable
       $LOCALDOMAIN  is  populated,  this name will be appended to unqualified
       host names.  Additional rewriting of local to public names  is  facili‐
       tated  in  case  the file /etc/dnswritefile exists and is populated, or
       alternatively the environment variable $DNSREWRITEFILE points to a dif‐
       fernent file.

ENVIRONMENT VARIABLES READ
       sslserver acknowledges the environment variable MAXCONIP="n" where n is
       the number of sslserver children spawned for  a  particular  remote  IP
       address.  n is restricted to the general connection limit c provided as
       call argument.  MAXCONIP is typically defined in sslserver's cdb for  a
       given  condition and thus only active meeting those.  MAXCONIP defaults
       0 meaning no restriction.

SSL ENVIRONMENT VARIABLES READ
       These variables define the run-time environment of  sslserver  and  are
       used to specify X509 certificates and keyfile per connection.

       $SSL_USER=name
              The user, reading the certificates and keyfile.

       $SSL_GROUP=group
              The respective user group.

       $SSL_UID=uid
              The numerical UID of the $SSL_USER.

       $SSL_CHROOT=path
              Perform  reading  of  certificates  and keyfile in a $SSL_CHROOT
              jail.

       $CAFILE=path
              If set, overrides the compiled-in CA file  name.   The  CA  file
              contains  the list of CAs used to verify the client certificate.
              Certificates in $CAFILE are processed when the server starts.

       $CADIR=path
              If set, overrides the compiled-in CA  directory  name.   The  CA
              directory  contains certificates files used to verify the client
              certificate.  This list augments the list  from  $CAFILE.   Cer‐
              tificates  in  $CADIR are processed during certificate verifica‐
              tion.

       $CERTFILE=path
              If set, overrides the compiled-in certificate  file  name.   The
              server presents this certificate to clients.

       $CERTCHAINFILE=path
              If  set,  overrides  the compiled-in certificate chainfile name.
              The server presents this list of certificats to clients.   Note:
              Providing  $CERTCHAINFILE  has  precedence over $CERTFILE.  Cer‐
              tificates in this file needs to be 'ordered' starting  from  the
              uppermost  root certificates and placing your host's certificate
              at the end.

       $CIPHERS=string
              If set, override the compiled-in SSL cipher  list  defining  the
              security  level  for  the connection.  A typical choice would be
              'TLSv1+HIGH:!SSLv2:!MD5'.

       $DHFILE=path
              If set, overrides the compiled-in DH parameter file name.

       $KEYFILE=path
              If set, overrides the compiled-in key file  name.   The  key  is
              used  when  loading the server certificate.  Setting $KEYFILE to
              the empty instructs the server not to use a keyfile when loading
              it's certificate.

       $VERIFYDEPTH=n
              If  set,  overrides the compiled-in verification depth. Default:
              1.

       $CCAFILE=path
              If set, overrides the compiled-in client CA file name for client
              certificate  request.   The  client CA file contains the list of
              CAs sent to the client when  requesting  a  client  certificate.
              Note:  Setting of $CCAFILE is required while using the option -z
              or -m.  However, declaring $CCAFILE="-" disables (on a  per-con‐
              nection base) the client certificate request.

       $CCAVERIFY
              If  set, sslserver requests a valid client certificate on a per-
              connection base, unlike the general option -z.

SSL ENVIRONMENT VARAIBLES SET
       In case sslserver is called with the option -e, the  following  mod_ssl
       environment variables are provided:

       SSL_PROTOCOL
              The TLS protocol version (SSLv3, TLSv1, ...).

       SSL_SESSION_ID
              The hex-encoded SSL session id.

       SSL_CIPHER
              The cipher specification name.

       SSL_CIPHER_USEKEYSIZE
              Number of cipher bits (actually used).

       SSL_CIPHER_ALGKEYSIZE
              Number of cipher bits (possible).

       SSL_VERSION_INTERFACE
              The mod_ssl program version.

       SSL_VERSION_LIBRARY
              The OpenSSL program version.

       SSL_CLIENT_M_VERSION
              The version of the client certificate.

       SSL_CLIENT_M_SERIAL
              The serial of the client certificate.

       SSL_CLIENT_S_DN
              Subject DN in client's certificate.

       SSL_CLIENT_S_DN_x509
              Component of client's Subject DN.

       SSL_CLIENT_I_DN
              Issuer DN of client's certificate.

       SSL_CLIENT_I_DN_x509
              Component of client's Issuer DN.

       SSL_CLIENT_V_START
              Validity of client's certificate (start time).

       SSL_CLIENT_V_END
              Validity of client's certificate (end time).

       SSL_CLIENT_A_SIG
              Algorithm used for the signature of client's certificate.

       SSL_CLIENT_A_KEY
              Algorithm used for the public key of client's certificate.

       SSL_CLIENT_CERT
              PEM-encoded client certificate.

       SSL_CLIENT_CERT_CHAIN n
              PEM-encoded certificates in client certificate chain.

       SSL_CLIENT_VERIFY
              NONE, SUCCESS, GENEROUS or FAILED:reason.

       SSL_SERVER_M_SERIAL
              The serial of the server certificate.

       SSL_SERVER_S_DN
              Subject DN in server's certificate.

       SSL_SERVER_S_DN_x509
              Component of server's Subject DN.

       SSL_SERVER_I_DN
              Issuer DN of server's certificate.

       SSL_SERVER_I_DN_x509
              Component of server's Issuer DN.

       SSL_SERVER_V_START
              Validity of server's certificate (start time).

       SSL_SERVER_V_END
              Validity of server's certificate (end time).

       SSL_SERVER_A_SIG
              Algorithm used for the signature of server's certificate.

       SSL_SERVER_A_KEY
              Algorithm used for the public key of server's certificate.

       SSL_SERVER_CERT
              PEM-encoded server certificate.

       For  SSL_CLIENT_x_DN_x509 and SSL_SERVER_x_DN_x509, x509 denotes a com‐
       ponent of the DN: C, ST, L, O, OU, CN, T, I, G, S, D, UID, Email.


       Other SSL environment variables set:

       PROTO, SSLLOCALHOST, SSLLOCALIP,  SSLLOCALPORT,  SSLREMOTEHOST,  SSLRE‐
       MOTEINFO, SSLREMOTEIP, SSLREMOTEPORT.


       TCP environment variables set:

       TCPLOCALHOST,  TCPLOCALIP,  TCPLOCALPORT, TCPREMOTEHOST, TCPREMOTEINFO,
       TCPREMOTEIP, TCPREMOTEPORT.


       TCP6 environment variables set:

       TCP6INTERFACE, TCP6LOCALHOST, TCP6LOCALIP,  TCP6LOCALPORT,  TCP6REMOTE‐
       HOST, TCP6REMOTEIP, TCP6REMOTEPORT.

LOGGING AND ERROR MESSAGES
       sslserver  prints  particular  state information for individual connec‐
       tions in case -v is specified. Here, the local and remote IP  addresses
       and  port together with the number of used/available/ip connection lim‐
       ited children:

         sslserver: status 1/40/0
         sslserver: pid xxxx from <ip>
         sslserver: [ok|deny] xxxx <local>:<localip>:<localport> <remotehost>:<remoteip>:<remoteport>
         sslserver: ended by xyz status nnnn

       If MAXCONIP is given as global environment variable, one may encounter:

         sslserver: status z/40/<maxconip>
         sslserver: WARNING ip connection limit of <maxconip> exceeded for: <remoteip>

       Rather, if MAXCONIP is read from the cdb, the following  message  might
       appear:

         sslserver: status 1/40/0
         sslserver: pid xxxx from <ip>
         sslserver: deny xxxx ... ip connection limit:<maxconip> exceeded
         sslserver: ended by xyz status nnnn

       In all cases, the resolved host names depends on the usage of l, -h and
       -p.  If -V is instead given as argument, lines like

         sslserver: tls xxxx accept TLSv1.2:ECDH-RSA-AES256-GCM-SHA384
         sslserver: tls xxxx accept TLSv1.3:TLS_CHACHA20_POLY1305_SHA256

       show additionally the negotiated cipher suite.

       Error and particular messages

       TLS error messages are provided, if possible:

       sslerver: error: (111) unable to speak TLS for pid: ... DH lib

       TLS handshake failure.

       sslserver: error: (111) unable to accept TLS for pid: ... system lib

       The remote socket was prematurely closed;  usually  because  the  X.509
       cert was not accepted by the client.

       sslserver: info: valid client cert received for pid: <pid>

       A client X.509 cert has been accepted for mutual authentication.

SEE ALSO
       sslhandle(1), sslclient(1), sslconnect(1), sslcat(1), https@(1), ucspi-
       tls(2), tcprules(1), tcprulescheck(1), tcpserver(1), tcp-environ(5)

REFERENCE
       http://httpd.apache.org/docs/2.4/mod/mod_ssl.html



                                                                  sslserver(1)