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groupdump - dumps group assignment lists for mcntp to stdout


groudump [-v]
groudump [acl-file]


The groupdump utility tries to get every packet with group assignments, parses it and dumps the result to stdout.

These assignment list carry information what newsgroup will be distribut- ed by which sender host in which multicast group. A receiver that wants to get NetNews articles can look up is this assignment list who carries the wanted newsgroup can can then join the wanted multicast group.

If an access list is given by the file acl-file as argument to groupdump it is read and every incoming packet is checked if the sender host is matched by the access list. This to help you check if incoming announce- ments come from your friends or not; this is useful if you have set up access control list for mcrcv(8) or yawgmoth(8) and want to know if they are right.

Groupdump opens UDP socket number 5418 (``mcntp'') for reading and gets member of the IP-multicast group This group has officially been assigned by IANA and has the name mcntp-directory.

When option -v is given, groupdump displays the mcntp version and exits.


acl-file is the path to a file that contains an access control list (see acl(3) for details on the contents of the file).

See Also

acltest(1) , mcxmit(8) , mcrcv(8) , netstat(1) , tcpdump(8) , acl(3) , mcntp(5)


The groupdump command is part of the diploma thesis Transport of NetNews via IP-multicast


Heiko W.Rupp (hwr@pilhuhn.de)


The manpage promises more processing of the packet than is actually done. Besides this:

None known yet

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$Id: groupdump.1.html,v 1.8 2001/11/22 10:24:37 pilhuhn Exp $