[Search for users] [Overall Top Noters] [List of all Conferences] [Download this site]

Conference azur::mcc

Title:	DECmcc user notes file. Does not replace IPMT.
Notice:	Use IPMT for problems. Newsletter location in note 6187
Moderator:	TAEC::BEROUD

Created:	Mon Aug 21 1989
Last Modified:	Wed Jun 04 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	6497
Total number of notes:	27359

1388.0. "%DNS-E-NOCOMMUNICATION error on SECOND TO LAST entity" by CUJO::HILL () Sun Aug 25 1991 22:15

    Here's a new slant on the old %DNS-E-NOCOMMUNICATION error.
    
    From FCL, I can issue any one of the following commands:
    
    MCC> DIR NODE4 *
    MCC> DIR SNMP *
    MCC> DIR ICMP *
    MCC> DIR BRIDGE *
    MCC> DIR TERMINAL_SERVER *
    MCC> DIR STATION *
    MCC> DIR NODE *
    
    In EVERY case, MCC performs a successful directory look up until it
    reaches the SECOND TO LAST entity instance, at which point I get this:
    
    The requested operation cannot be completed
                          MCC Routine Error = %DNS-E-NOCOMMUNICATION, Unable
    to communicate with DNS server
    
    NOTE:  It does not matter how many entity instances or how few, I still
    get the same message at the SECOND TO LAST instance.
    
    Any ideas?  I'll be looking at DNS documentation in the mean time.
    
    -Dan

T.R Title User Personal
Name Date Lines

1388.1 MCC uses look-ahead buffer TRM::KWAK Mon Aug 26 1991 13:08 45

T.R	Title	User	Personal Name	Date	Lines
1388.1	MCC uses look-ahead buffer	TRM::KWAK		`Mon Aug 26 1991 13:08`	45
	RE: .0 When you issue "MCC> dir node4 * " command, the entire DNS namespace (every directory) is searched by DNS Clerk in your system. If any one directory in the namespace is not accessible, you may get the %DNS-E-NOCOMMUNICATION error. If a directory (either master or read-only copy) resides in a remote clearinghouse, and the namesever for the clearinghouse is not reachable, DNS clerk returns %DNS-E-NOCOMMUNICATION status. One way of checking that every directory is reachable is to use an example program which displays sub-directories of a directory of a namespace, and all objects stored in them. The example (DNS_OBJ_WALK.C) is in Topic # 34.5 in NOTED::DNS_PROGRAMMER notes conference. (Note 34.8 tells how to link the program) I think that if a directory is not reachable, the program may display the %DNS-E-NOCOMMUNICATION status. Another way of checking that every directory is reachable is to use DNS$Control program. If your namespace has a small number of directories, you can use DNS$Control command for each directory: $ mcr dns$control DNS> sho dir .dna_node known object DNS> sho dir .mydir known object . . . . >> In EVERY case, MCC performs a successful directory look up until it >> reaches the SECOND TO LAST entity instance, at which point I get this: The reason for the lookup operation failure showing up at the SECOND TO LAST instance is that MCC does have a look-ahead buffer. After the last instance is read from the DNS Clerk (meaning the second to last instance is returned to the caller, and the last instance is in the look-ahead buffer), DNS Clerk fails to access a directory, the error status is passed to the caller. William

RE: .0

When you issue "MCC> dir node4 * " command, the entire DNS namespace (every
directory) is searched by DNS Clerk in your system.
If any one  directory in the namespace is not accessible, you may get the
%DNS-E-NOCOMMUNICATION error.

If a directory (either master or read-only copy) resides in a remote 
clearinghouse, and the namesever for the clearinghouse is not reachable, 
DNS clerk returns %DNS-E-NOCOMMUNICATION status.

One way of checking that every directory is reachable is to use an example 
program which displays sub-directories of a directory of a namespace, and all
objects stored in them. The example (DNS_OBJ_WALK.C) is in Topic # 34.5 in 
NOTED::DNS_PROGRAMMER notes conference. (Note 34.8 tells how to link the 
program)  I think that if a directory is not reachable, the program may
display the %DNS-E-NOCOMMUNICATION status.

Another way of checking that every directory is reachable is to use DNS$Control
program.  If your namespace has a small number of directories, you can use 
DNS$Control command for each directory:

	$ mcr dns$control
	DNS> sho dir .dna_node known object
	DNS> sho dir .mydir known object
		.
		.
		.
		.




>>    In EVERY case, MCC performs a successful directory look up until it
>>    reaches the SECOND TO LAST entity instance, at which point I get this:

The reason for the lookup operation failure showing up at the SECOND TO LAST 
instance is that MCC does have a look-ahead buffer. After the last instance
is read from the DNS Clerk (meaning the second to last instance is returned to
the caller, and the last instance is in the look-ahead buffer), DNS Clerk
fails to access a directory, the error status is passed to the caller.


William