2012-12-22_03-15-47__Remote_Management

7/26/2019 2012-12-22_03-15-47__Remote_Management

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Remote Management

SSH

This Lecture explains how to set up Secure Shell (SSH) access on the Vyatta system.

SSH Configuration

Secure Shell (SSH) provides a secure mechanism to log on to the Vyatta system andaccess the Command Line Interace (CLI). Coniguring SSH is optional! "ut isrecommended to provide secure remote access to the Vyatta system. In addition tothe standard password authentication provided "y SSH! shared pu"lic #eyauthentication is also availa"le.

Example -1 ena"les SSH or password authentication on the deault port (port $$)!as shown in %igure &'&. y deault! only SSH version $ is ena"led.

Figure1 na"ling SSH access

To ena"le the SSH service on the Vyatta system! perorm the ollowing steps inconiguration mode*

Example 1 na"ling SSH accessStep Command

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''Create the coniguration node or vyatta@R1# set servie ss!the SSH service.'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''Commit the inormation vyatta@R1# ommit Restarting "penS$ Seure S!ell server% ss!d&'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''Show the coniguration. vyatta@R1# s!o' servie

ss! ( )

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''


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SSH Commands

servie ss!

na"les SSH as an access protocol on the Vyatta system.

Syntax%

set servie ss!delete servie ss!s!o' servie ss!

*uidelines%+se this command to conigure the system to allow SSH re,uests rom remotesystems to the local system.

Creating the SSH coniguration node ena"les SSH as an access protocol. y deault!

the router uses port $$ or the SSH service! and SSH version $ alone is used.

+se the setorm o this command to create the SSH coniguration.

+se the deleteorm o this command to remove the SSH coniguration. I you deletethe SSH coniguration node you will disa"le SSH access to the system.

+se the s!o'orm o this command to view the SSH coniguration.

servie ss! allo'rootSpeciies that root logins are to "e allowed on SSH connections.

Syntax%set servie ss! allo'-rootdelete servie ss! allo'-roots!o' servie ss!

*uidelines

+se this command to speciy that root logins are to "e allowed on SSH connections.

+",E% The rootaccount is oten the target o external attac#s so its use is discouraged. The vyattaaccount provides suicient privileges to administer the system.

+se the setorm o this command to speciy that root logins are to "e allowed onSSH connections.

+se the deleteorm o this command to restore the deault allow'root coniguration.

+se the s!o'orm o this command to view the coniguration.


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servie ss! disale!ostvalidationSpeciies that SSH should not validate clients via reverse -S loo#up.

Syntax%set servie ss! disale-!ost-validationdelete servie ss! disale-!ost-validation

s!o' servie ss!

*uidelines

+se this command to speciy that SSH should not resolve client /T01reverse'-Srecords via a reverse -S (/T0) loo#up. This process can "e time consuming andcause long delatys or clients trying to connect.

+se the set orm o this command to speciy that SSH should not resolve client/T01reverse'-S records via a reverse -S (/T0) loo#up.

+se the deleteorm o this command to restore the deault coniguration and allowreverse -S loo#ups.

+se the s!o'orm o this command to view the coniguration.

servie ss! disalepass'ordaut!entiation

Speciies that SSH users are not to "e authenticated using passords.

Syntaxset servie ss! disale-pass'ord-aut!entiationdelete servie ss! disale-pass'ord-aut!entiations!o' servie ss!

*uidelines

+se this command to speciy that SSH users are not to "e authenticated usingpasswords. This is typically done in order or SSH users to "e authenticated usingshared pu"lic #eys instead. Shared pu"lic #ey authentication is less suscepti"le to"rute orce guessing o common passwords. I password authentication is disa"ledthen shared pu"lic #eys must "e conigured or user authentication.

+se the setorm o this command to speciy that users are not to "e authenticated "yusing passwords.

+se the deleteorm o this command to restore the deault coniguration and allowauthentication "y passwords.

+se the s!o' orm o this command to view the coniguration.


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servie ss! listenaddress .ipv/0Conigures access to SSH on a speciic address.

Syntaxset servie ss! listen-address ipv2delete servie ss! listen-addressipv2

s!o' servie ss! listen-address

*uidelines

y deault re,uests to access SSH will "e accepted on any system I/ address.+se this command to conigure the system to accept re,uests or SSH access onspeciic addresses. This provides a way to limit access to the system.

+se the setorm o this command to conigure the system to accept re,uests or SSHaccess on speciic addresses.

+se the deleteorm o this command to remove a listen'address.

+se the s!o' orm o this command to view the listen'address coniguration.

servie ss! port .port0

Speciies the port the system will use or the SSH service.

Syntaxset servie ss! port portdelete servie ss! ports!o' servie ss! port

*uidelinesy -eault SSH Listens on port $$+se this command to speciy the port the system will use or the SSH service.

+se the setorm o this command to speciy the port the system will use or the SSHservice.

+se the deleteorm o this command to restore the deault port coniguration.

+se the s!o'orm o this command to view the port coniguration.


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servie ss! protoolversion .version0Speciies which versions o SSH are ena"led.

Syntaxset servie ss! protool-version versiondelete servie ss! protool-version

s!o' servie ss! protool-version

*uidelines

SSH version $ is ena"led+se this command to speciy which versions o SSH are ena"led.

+se the setorm o this command to speciy which versions o SSH are ena"led.

+se the deleteorm o this command to restore the deault protocol'versionconiguration.

+se the s!o'orm o this command to view the protocol'version coniguration.


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S+M

S3/ (Simple etwor# 3anagement /rotocol) is a mechanism or managingnetwor# and computer devices.S3/ uses a manager1agent model or managing the devices. The agent resides inthe device! and provides the interace to the physical device "eing managed. The

manager resides on the management system and provides the interace "etween theuser and the S3/ agent. The interace "etween the S3/ manager and the S3/agent uses a 3anagement Inormation ase (3I) and a small set o commands toexchange inormation.The Vyatta system supports S3/ over "oth I/v2 and I/v4 networ#s.

M2 "3ets

5 3I contains the set o varia"les1o"6ects that are managed (or example! 3T+ ona networ# interace). Those o"6ects are organi7ed in a tree structure where eacho"6ect is a lea node. ach o"6ect has its uni,ue 8"6ect Identiier (8I-).

There are two types o o"6ects* scalar and ta"ular. 5 scalar o"6ect deines a singleo"6ect instance. 5 ta"ular o"6ect deines multiple related o"6ect instances that aregrouped in 3I ta"les. %or example! the uptime on a device is a scalar o"6ect! "utthe routing ta"le in a system is a ta"ular o"6ect.

,raps

In addition to 3I o"6ects! the S3/ agent on a device can ormulate alarms andnotiications into S3/ traps. The device will asynchronously send the traps to theS3/ managers that are conigured as trap destinations or targets. This #eeps thenetwor# manager inormed o the status and health o the device.

S+M CommandsS3/ commands can "e used to read or change coniguration! or to perorm actionson a device! such as resetting it. The set o commands used in S3/ are* *E,4*E,-+E5,4 *E,-RES"+SE4 SE,4 and ,R6&9 *E,and *E,-+E5,are used "y the manager to re,uest inormation a"out an o"6ect. These commands are used to view coniguration or status! or to poll inormation such as statistics.9 SE,is used "y the manager to change the value o a speciic o"6ect. Setting a coniguration o"6ect changes the device:s coniguration. Setting an executa"le o"6ect perorms an action! such as a ile operation or a reset.

9 *E,-RES"+SEis used "y the S3/ agent on the device to return the re,uested inormation "y *E,or *E,-+E5,! or the status o the SE,

operation.9 The ,R6command is used "y the agent to asynchronously inorm the manager a"out events important to the manager.

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2012-12-22_03-15-47__Remote_Management