ru.unix.bsd

 
 - RU.UNIX.BSD ------------------------------------------------------------------
 From : Victor Sudakov                       2:5005/149     27 Jul 2003  00:46:59
 To : Spartak Radchenko
 Subject : Re: ipnat и протоколы прикладного уровня
 -------------------------------------------------------------------------------- 
 

 Spartak Radchenko wrote:
 
 > VS>> И на один работает. Только не с ipnat.
 > SO> 
 > SO> Это невозможно физически.
 > SO> В открытом хидере нету необходимой информации, остальное пошифрованно.
 > 
 > Ты забыл про Call ID.
 
 И именно с ним умеет работать natd. См. выдержку из alias_pptp.c
 
    Alias_pptp.c performs special processing for PPTP sessions under TCP.
    Specifically, watch PPTP control messages and alias the Call ID or the
    Peer's Call ID in the appropriate messages.  Note, PPTP requires
    "de-aliasing" of incoming packets, this is different than any other
    TCP applications that are currently (ie. FTP, IRC and RTSP) aliased.
 
    For Call IDs encountered for the first time, a PPTP alias link is created.
    The PPTP alias link uses the Call ID in place of the original port number.
    An alias Call ID is created.
 
    For this routine to work, the PPTP control messages must fit entirely
    into a single TCP packet.  This is typically the case, but is not
    required by the spec.
 
    Unlike some of the other TCP applications that are aliased (ie. FTP,
    IRC and RTSP), the PPTP control messages that need to be aliased are
    guaranteed to remain the same length.  The aliased Call ID is a fixed
    length field.
 
    Reference: RFC 2637
 
    Initial version:  May, 2000 (eds)
 -- 
 Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
 2:5005/149@fidonet http://vas.tomsk.ru/
 --- tin/1.5.17-20030407 ("Peephole") (UNIX) (FreeBSD/4.8-RELEASE (i386))
  * Origin: CISA Ltd. InterNetNews site (2:5005/149@fidonet)
 
 

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