Paul Sherman

Na Li

Just EnoughSAS

to Identify Yourself in a

Networked World

www.idiom.com / ~sherman / paul / pubs / netcmdArticle & Slides:

Overview

• What’s wrong with networking

• Topology

• Authentication Process

• Pitfalls

• The net.exe command

• Example

• A %netauth utility macro

What’s Wrong With Networking

• Permission denied.

• Access is denied.

• Lost connection ( Re-boot and forget to re-map? )

• But it runs on my local PC!

The Network is Your Friend

• Time, Share & Use – in a single command

• %sysexec() “x” gets you to DOS prompt

• Everything has a UNC path:

• Tell %netauth() whenever you need to CONNECT or DISCONNECT a remote host

Hostname

Sharename

file systempath\\ \ \

• Typical of many large corporate intranets

• Managed centrally

• Easier to administrate

• Synonymous access to all hosts

Domains

CRFPROTSAFETY

BIOMETRIC

EFFICACY

JLO

JEFF

MARY

codcor.psug.org

CODCORDC01

PDC

Network Topology

• Small labs and home offices

• Managed individually

• Cumbersome to administrate

• Easier to develop applications within

• Less prone to system-wide failures

Workgroups

CRFPROT

SAFETY

BIOMETRIC

EFFICACYJLOJEFF

MARY

Network Topology

• Client contacts Domain Controller (DC)

• DC forwards request to host

• Host responds to DC with accept or deny

• DC grants access to Client

• Client & Host can now communicate

The Authentication Process

The Authentication Process

CLIENT HOST

DOMAINCONTROLLER

PDC

auth request

respond

proceed

grant

CLIENT HOST auth

grant

proceed

Wor

kgro

upD

omai

n

A Word About Scope

Get Close

Pitfall #1

A Word About Scope

MarySAFETY

runsas

CRFPROTrunsas

John’s code (a) Fails(b) Writes output where it doesn’t belong(c) All of the above

copy g:\raw.sd2 c:\copy c:\ae.prn g:\

copy g:\marydat.sd2 c:\

C:\user\john\sas

G:

C:\user\mary\sas\dev

map G:

map G:

marydat.sd2marydat.sd2

raw.sd2ae.prn

ae.prn

raw.sd2

John

Pitfall #1

More Words of Scope

• Network resources are global to all users

• Avoid absolute drive letter mappings• Use “UNC” path references, always

net use \\safety\c$\user\john\sas/user:john j

net use \\safety\c$\user\mary\sas\dev/user:mary m

John:

Mary:

Pitfall #1

auth. Jeff

auth. Melissa

runsas

runsas

Credential Conflict

Jeff

Read & Write

net use \\crfprot\ib /user:jeff j

net use \\crfprot\ib /user:melissa m

This set of credentials conflicts with an existing set of credentials

CRFPROT

Read-only

BIOMETRIC

Melissa

Pitfall #2

Avoiding Credential Conflict

• Schedule remote jobs synchronously, or• Use dotted-decimal addressing

net use \\crfprot\ib /user:jeff j

net use \\1.2.3.4\ib /user:melissa m

ping the host to find its dotted-decimal address

Pitfall #2

runsas

The Case of the Wrong Case

Jeff

net use \\biometric\patprof\peopledata /user:jeff j

BIOMETRIC123-45-6789.doc

Be careful with case in Auth & Usage !

Permission Denied

copy c:\123-45-6789.doc \\biometric\PatProf\PeopleData

Pitfall #3

Networking “Best Practice”

• Separate “Auth” and “Usage” tasks• Assert credentials with IPC$ virtual share• Work with remote host as normal• De-auth the IPC$ share when finished

net use \\safety\ipc$ /user:melissa mcopy \\safety\ae\x.prn \\safety\lab\x.prndel \\safety\logs\myprog.txt

net use \\safety\ipc$ /d

The net.exe Command

• Part of Windows since Win95

C:\> net timeC:\> net viewC:\> net use

Check & Sync time

Query shares & volumes

Mount & Unmount drives

Synchronizing Time

John EFFICACY

2:43 PM 3:06 PM

x ”net time \\efficacy.psug.org /set /y”;

3:06 PM

Example

Learning to Share

Mary EFFICACY

net view \\efficacy.psug.org

demogsurvivalresponse

Example

• Send message at start & end of remote work• Be careful with case of host, share and path

Using %netauth()

%netauth(CONNECT);

x “net time \\host /set /y”;x “copy c:\sas\work\out\*.gif \\host\web\Charts”;libname inlib “c:\sas\work\lib”;libname outlib “\\host\web\SASLib”;proc datasets; copy inlib outlib; run;libname outlib clear;libname inlib clear;

%netauth(DISCONNECT);

How %netauth() Works%macro netauth( mode ); %local domain_a ua pa domain_b ub pb; %let domain_a=ddd; %let ua=uuu; %let pa=ppp; %let domain_b=ddd; %let ub=uuu; %let pb=ppp;

options xsync noxwait;

%if %trim(%upcase(&mode.)) eq CONNECT %then %do; x “net use \\crfprot\ipc$ /user:&domain_a.\&ua. &pa.”; x “net use \\safety\ie /user:&domain_b.\&ub. &pb.”;

%if %trim(%upcase(&mode.)) eq DISCONNECT %then %do; x “net use \\crfprot\ipc$ /d”; x “net use \\safety\ie /d”;

%end; %else %do; put ERROR: bad &mode. Expected CONNECT or DISCONNECT); %end;%mend;

Very important

Conclusion

• Manage & control remote hosts with net.exe

• Authenticate• What you need• When you neet it• Never longer than necessary

• Never use drive letters!

• UNC paths are Linux-compliant, too

• Be careful with case

More Info …

• Microsoft Knowledge Base

219898 – “How the Bad Password Count is Incremented in Windows NT”

314984 – “How to create and delete hidden or administrative shares on client computers”

• Na Li“Applications for Running DOS Commands within SAS”

PharmaSUG 2005, Posters, PO-13.

About the Speakers

Speaker

Telephone

E-Mail

Web Site

Na LiSr. Project Analyst

(408) 990 - 7293

nli @ pcyc.com

www.idiom.com / ~sherman / paul / pubs / netcmd

Paul D ShermanElectrical Engineer

(408) 383 - 0471

sherman @ idiom.com