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       sockd.route - Route file for multi-homed SOCKS proxy server




       The  file /etc/sockd.route is used by the SOCKS server program sockd to
       determine which of its network interfaces it  should  use  to  reach  a
       given  destination host. It is needed only if your SOCKS server host is
       multi-homed and your version of sockd supports  RBIND.   A  multi-homed
       host  is  a  host  with  more  than one network interfaces and with its
       IP_FORWARDING turned off. Only the multi-homed version of sockd can  be
       run  on  such  hosts.   You  can find out the version of your sockd (or
       rsockd) by command

       sockd -ver


       rsockd -ver

       A line in the file can be up to 1024 characters  long.  Lines  starting
       with a#are comments. Non-comment lines must be of the form

       if_addr        dst_addr  dst_mask

       All  three  fields  are  required  and are separated by spaces or tabs.
       Each filed is specified in the usual dotted form of IP addresses, e.g.,   if_addr  must  be  the  IP address of one of the network
       interfaces on the SOCKS server host.  dst_addr specifies either the  IP
       address  of  a  host,  a network, or a subnet in the usual dotted form,
       e.g.,, or  a  domain  name,  e.g.,  dst_mask
       specifies  mask  for the IP address used in dst_addr.  Bits in dst_mask
       that are set to 0 indicate the  bit  positions  to  be  ignored  during
       comparison  of IP addresses. So, specifying in dst_mask
       demands an exact match  with  dst_addr,  whereas  in  dst_mask
       causes a matching with any given destination address regardless of what
       is specified for dst_addr. If a domain name is used for  dst_addr,  the
       contents  of  dst_mask  are  ignored,  though it must still be supplied
       (simply use  If the domain name  starts  with  a  period,  it
       specifies  a  zone  and  matches  all  domain  names  within that zone,
       otherwise it matches only the domain name itself. For example,
       matches  only  xyz.comP,  while macthes not only, but
       also and, among others.  The  special
       symbol  ALL  (which  must be entirely in uppercase) matches everything.
       Domain names are otherwise case-insentive.

       When using a domain name in dst_addr,  you  have  be  very  careful  in
       maintaining   your   DNS   setup.   See  the  last  few  paragraphs  in

       When a multi-homed sockd receives a network request,  it  first  checks
       with  /etc/sockd.fc  (or /etc/sockd.conf) to decide whether the request
       should be allowed or denied.  For  an  allowable  request,  sockd  then
       checks  the  given  destination  IP  address or domain name against the
       dst_addr dst_mask pair in /etc/sockd.route, one line at a line. Once  a
       match  is  found,  the  network  interface of the corresponding if_addr
       field is used for connection to the destination host.  Remaining  lines
       in  the  file are skipped. Therefore the order of the lines in the file
       is of extreme importance. If no match is found throughout the  file,  a
       line indicating the error is produced using syslog with facility daemon
       and level err and the request is ignored.

       You have the option  of  using  the  frozen  route  file  /etc/
       instead   of   /etc/sockd.route.   The   frosen  file  is  produced  by
       make_sockdfr and is essentially the memory image of  the  parsed  route
       file.  Using it can reduce the start-up delay of the SOCKS server since
       it eliminate the need for parsing. Since the SOCKS server always  looks
       for /etc/ first, be sure that you always run make_sockdfr every
       time after you modifify /etc/sockd.route.


       Suppose you have a dual-homed host with interface  connecting
       to  your  internal  Class  B  network  129.1, and interface
       connecting to the outside world. If you only use the  SOCKS  server  to
       provide  connections  to  outside hosts, then the file /etc/sockd.route
       only needs one line:

       If you also use the SOCKS server  to  provide  connection  to  internal
       hosts as well, then two lines would suffice:

       Note that these two lines must be in the order given above.

       If you prefer using domain name instead, the lines should be

       assuming that is your domain.


       dump_sockdfr(8), make_sockdfr(8), sockd(8),

                                  May 6, 1996