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Deploy ASA VPN Load-Balancing Cluster

In this article, I would like to provide step-by-step instructions on how to quickly deploy the most scalable Remote-Access VPN access scheme based on AnyConnect and Cisco ASA - VPN Load Balancing Cluster .


Introduction: Many companies around the world, in view of the current environment with COVID-19, are making efforts to transfer their employees to remote mode. Due to the massive transition to remote work, the load on existing VPN gateways of companies increases critically and a very fast ability to scale them is required. On the other hand, many companies are forced to rush to learn from scratch such a thing as remote work.


In order to help businesses implement convenient, secure, and scalable VPN access for employees as quickly as possible, Cisco provides licenses for the AnyConnect multi-function SSL-VPN client for up to 13 weeks. You can also take ASAv for a test (Virtual ASA for VMWare / Hyper-V / KVM hypervisors and AWS / Azure cloud platforms) from authorized partners or by contacting your Cisco representative .


The AnyConnect COVID-19 license issuing procedure is described here .


I prepared step-by-step instructions for a simple VPN option for deploying a Load-Balancing cluster as the most scalable VPN technology.


The following example will be quite simple from the point of view of the authentication and authorization algorithms used, but it will be a good option for a quick start (which is very lacking now) with the possibility of in-depth adaptation to your needs during the deployment process.


: VPN Load Balancing Cluster failover , ASA ( ) Remote-Access VPN . C , VPN VPN . VPN .


( ) , , Primary . Load-Balancing , , , . .


VPN Load-Balancing .


VPN Load-Balancing ASA 5512-X .


ASA VPN Load-Balancing , .



:



:


  1. ASAv (ASAv5/10/30/50).


  2. INSIDE/OUTSIDE VLAN (Outside VLAN, INSIDE , . ), L2 .


  3. :


    • ASAv 100/.
    • Smart-Account: https://software.cisco.com/ -> Smart Software Licensing
    • New Token
    • , Allow export-controlled functionality… VPN. , - .
    • Create Token, , ASAv, :
    • C,D,E ASAv.
    • , telnet. ASA ( ASA-1). telnet outside , , security-level 100 outside, .
      !
ciscoasa# conf t
!
ciscoasa(config)# int gi0/0
ciscoasa(config)# nameif outside
ciscoasa(config)# ip address 192.168.31.30 255.255.255.0
ciscoasa(config)# no shut
!
ciscoasa(config)# int gi0/1
ciscoasa(config)# nameif inside
ciscoasa(config)# ip address 192.168.255.2 255.255.255.0
ciscoasa(config)# no shut
!
ciscoasa(config)# telnet 0 0 inside
ciscoasa(config)# username admin password cisco priv 15
ciscoasa(config)# ena password cisco
ciscoasa(config)# aaa authentication telnet console LOCAL
!
ciscoasa(config)# route outside 0 0 192.168.31.1
!
ciscoasa(config)# wr
!
    • Smart-Account ASA, .
      , ASA :
      • HTTPS ;
      • ( NTP);
      • DNS ;
    • telnet ASA Smart-Account.

    !
ciscoasa# conf t
!
ciscoasa(config)# clock set 19:21:00 Mar 18 2020
ciscoasa(config)# clock timezone MSK 3
ciscoasa(config)# ntp server 192.168.99.136
!
ciscoasa(config)# dns domain-lookup outside
ciscoasa(config)# DNS server-group DefaultDNS
ciscoasa(config-dns-server-group)# name-server 192.168.99.132 
!
!   DNS:
!
ciscoasa(config-dns-server-group)# ping ya.ru
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 87.250.250.242, timeout is 2 seconds:
!!!!!
!
!   NTP:
!
ciscoasa(config)# show ntp associations 
  address         ref clock     st  when  poll reach  delay  offset    disp
*~192.168.99.136   91.189.94.4       3    63    64    1    36.7    1.85    17.5
* master (synced), # master (unsynced), + selected, - candidate, ~ configured
!
!    ASAv  Smart-Licensing (    ,    100  )
!
ciscoasa(config)# license smart
ciscoasa(config-smart-lic)# feature tier standard
ciscoasa(config-smart-lic)# throughput level 100M
!
!              :
!call-home
!  http-proxy ip_address port port
!
!       Smart-Account  (<token>)   
!
ciscoasa(config)# end
ciscoasa# license smart register idtoken <token>

    • :


  4. SSL-VPN


    • SSH ASDM:


      !
ciscoasa# conf t
ciscoasa(config)# ssh ver 2
ciscoasa(config)# aaa authentication ssh console LOCAL
ciscoasa(config)# aaa authentication http console LOCAL
ciscoasa(config)# hostname vpn-demo-1
vpn-demo-1(config)# domain-name ashes.cc
vpn-demo-1(config)# cry key gen rsa general-keys modulus 4096 
vpn-demo-1(config)# ssh 0 0 inside  
vpn-demo-1(config)# http 0 0 inside
!
!   HTTPS  ASDM   445     SSL-VPN 
!
vpn-demo-1(config)# http server enable 445 
!

    • ASDM cisco.com, :


    • AnyConnect ASA ( Linux/Windows/MAC) Headend Deployment Package :


    • , , FTP ASA:


    • ASDM VPN- SSL-VPN ( ). FQDN (vpn-demo.ashes.cc), FQDN DNS IP OUTSIDE ( mapped , udp/443 (DTLS) tcp/443(TLS)). Certificate Verification .


      • Self-Signed ( )
        !
vpn-demo-1(config)# asdm image flash:/asdm-7131.bin
!
vpn-demo-1(config)# crypto ca trustpoint SELF
vpn-demo-1(config-ca-trustpoint)# enrollment self
vpn-demo-1(config-ca-trustpoint)# fqdn vpn-demo.ashes.cc
vpn-demo-1(config-ca-trustpoint)# subject-name cn=*.ashes.cc, ou=ashes-lab, o=ashes, c=ru
vpn-demo-1(config-ca-trustpoint)# serial-number             
vpn-demo-1(config-ca-trustpoint)# crl configure
vpn-demo-1(config-ca-crl)# cry ca enroll SELF
% The fully-qualified domain name in the certificate will be: vpn-demo.ashes.cc
Generate Self-Signed Certificate? [yes/no]: yes
vpn-demo-1(config)# 
vpn-demo-1(config)# ssl trust-point SELF
!
vpn-demo-1(config)# sh cry ca certificates 
Certificate
Status: Available
Certificate Serial Number: 4d43725e
Certificate Usage: General Purpose
Public Key Type: RSA (4096 bits)
Signature Algorithm: SHA256 with RSA Encryption
Issuer Name: 
serialNumber=9A439T02F95
hostname=vpn-demo.ashes.cc
cn=*.ashes.cc
ou=ashes-lab
o=ashes
c=ru
Subject Name:
serialNumber=9A439T02F95
hostname=vpn-demo.ashes.cc
cn=*.ashes.cc
ou=ashes-lab
o=ashes
c=ru
Validity Date: 
start date: 00:16:17 MSK Mar 19 2020
end   date: 00:16:17 MSK Mar 17 2030
Storage: config
Associated Trustpoints: SELF 
CA Certificate
Status: Available
Certificate Serial Number: 0509
Certificate Usage: General Purpose
Public Key Type: RSA (4096 bits)
Signature Algorithm: SHA1 with RSA Encryption
Issuer Name: 
cn=QuoVadis Root CA 2
o=QuoVadis Limited
c=BM
Subject Name: 
cn=QuoVadis Root CA 2
o=QuoVadis Limited
c=BM
Validity Date: 
start date: 21:27:00 MSK Nov 24 2006
end   date: 21:23:33 MSK Nov 24 2031
Storage: config
Associated Trustpoints: _SmartCallHome_ServerCA
      • , CA:
        • TrustPoint:
          !
vpn-demo-1(config)# asdm image flash:/asdm-7131.bin
!
vpn-demo-1# conf t
vpn-demo-1(config)# crypto ca trustpoint ashes-ca
vpn-demo-1(config-ca-trustpoint)#  enrollment terminal
vpn-demo-1(config-ca-trustpoint)#  fqdn vpn-demo.ashes.cc
vpn-demo-1(config-ca-trustpoint)#  subject-name cn=*.ashes.cc, ou=ashes-lab, o$
vpn-demo-1(config-ca-trustpoint)#  serial-number
vpn-demo-1(config-ca-trustpoint)#  crl configure
!
        • Trustpoint, ROOT CA:

        • ASA :
        • CSR VPN-:
        • CA CSR:
        • , :
        • ASA:
        • root-ca:
        • SSL TrustPoint:
          !
vpn-demo-1(config)# ssl trust-point ashes-ca
!

    • ASDM , :


    • :


      • , ( , . , split-tunnel-policy tunnelall . Split-Tunnel VPN )
      • 192.168.20.0/24 ( 10 30 ( #1)). VPN .
      • ASA ( , ), LDAP/RADIUS, Multi-Factor Authentication (MFA), Cisco DUO.
        !
vpn-demo-1(config)# http redirect outside 80
!
vpn-demo-1(config)# ip local pool vpn-pool 192.168.20.10-192.168.20.30 mask 255.255.255.0
!
vpn-demo-1(config)# access-list split-tunnel standard permit 192.168.0.0 255.255.0.0
!
vpn-demo-1(config)# group-policy SSL-VPN-GROUP-POLICY internal
vpn-demo-1(config)# group-policy SSL-VPN-GROUP-POLICY attributes
vpn-demo-1(config-group-policy)# vpn-tunnel-protocol ssl-client 
vpn-demo-1(config-group-policy)# split-tunnel-policy tunnelspecified
vpn-demo-1(config-group-policy)# split-tunnel-network-list value split-tunnel
vpn-demo-1(config-group-policy)# dns-server value 192.168.99.132
vpn-demo-1(config-group-policy)# default-domain value ashes.cc
vpn-demo-1(config)# tunnel-group DefaultWEBVPNGroup general-attributes
vpn-demo-1(config-tunnel-general)#  default-group-policy SSL-VPN-GROUP-POLICY
vpn-demo-1(config-tunnel-general)#  address-pool vpn-pool
!
vpn-demo-1(config)# username dkazakov password cisco
vpn-demo-1(config)# username dkazakov attributes
vpn-demo-1(config-username)# service-type remote-access
!
vpn-demo-1(config)# webvpn
vpn-demo-1(config-webvpn)#  enable outside
vpn-demo-1(config-webvpn)#  anyconnect image disk0:/anyconnect-win-4.8.03036-webdeploy-k9.pkg
vpn-demo-1(config-webvpn)#  anyconnect enable
!

    • (): , , . , RADIUS , Cisco Identity Services Engine:


      !
vpn-demo-1(config)# aaa-server RADIUS protocol radius
vpn-demo-1(config-aaa-server-group)# dynamic-authorization
vpn-demo-1(config-aaa-server-group)# interim-accounting-update
vpn-demo-1(config-aaa-server-group)# aaa-server RADIUS (outside) host 192.168.99.134
vpn-demo-1(config-aaa-server-host)# key cisco
vpn-demo-1(config-aaa-server-host)# exit
vpn-demo-1(config)# tunnel-group DefaultWEBVPNGroup general-attributes
vpn-demo-1(config-tunnel-general)# authentication-server-group  RADIUS 
!

      AD, AD, .


    • Transparent NAT :


      !
vpn-demo-1(config)# object network vpn-users
vpn-demo-1(config-network-object)#  subnet 192.168.20.0 255.255.255.0
!
vpn-demo-1(config)# nat (inside,outside) source static any any destination static vpn-users vpn-users no-proxy-arp

    • (): ASA ( tunnelall ) PAT, OUTSIDE,


      !
vpn-demo-1(config-network-object)# nat (outside,outside) source dynamic vpn-users interface
vpn-demo-1(config)# nat (inside,outside) source dynamic any interface
vpn-demo-1(config)# same-security-traffic permit intra-interface 
!

    • ASA , /32 , .
      , VPN , FQDN IP.

      ASA:

      VPN , , OSPF:


      !
vpn-demo-1(config)# access-list VPN-REDISTRIBUTE standard permit 192.168.20.0 255.255.255.0 
!
vpn-demo-1(config)# route-map RMAP-VPN-REDISTRIBUTE permit 1
vpn-demo-1(config-route-map)#  match ip address VPN-REDISTRIBUTE
!
vpn-demo-1(config)# router ospf 1
vpn-demo-1(config-router)#  network 192.168.255.0 255.255.255.0 area 0
vpn-demo-1(config-router)#  log-adj-changes
vpn-demo-1(config-router)#  redistribute static metric 5000 subnets route-map RMAP-VPN-REDISTRIBUTE

      ASA-2 , VPN , , , VPN :



  5. Load-Balancing .
    192.168.31.40 Virtual IP ( VIP — VPN ), Master REDIRECT . DNS /FQDN , VIP.


    !
vpn-demo-1(config)# crypto ikev1 enable inside
vpn-demo-1(config)# vpn load-balancing
vpn-demo-1(config-load-balancing)# interface lbpublic outside
vpn-demo-1(config-load-balancing)# interface lbprivate inside
vpn-demo-1(config-load-balancing)# priority 10
vpn-demo-1(config-load-balancing)# cluster ip address 192.168.31.40
vpn-demo-1(config-load-balancing)# redirect-fqdn enable
vpn-demo-1(config-load-balancing)# cluster key cisco
vpn-demo-1(config-load-balancing)# cluster encryption
vpn-demo-1(config-load-balancing)# cluster port 9023
vpn-demo-1(config-load-balancing)# participate
vpn-demo-1(config-load-balancing)#

    • :
    • AnyConnect ASDM.

      :

      AnyConnect , :

      , ASDM ASA, ASA .


: , VPN . , ASAv ASA. AnyConnect Posture ( ), Identity Services Engine.

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