Remote-access Guide

cisco asa remote access vpn nat ip address

by Felton Johnston III Published 2 years ago Updated 1 year ago
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ASA1 (config)# ip local pool VPN_POOL 192.168.10.100-192.168.10.200 mask 255.255.255.0 Remote users will get an IP address from the pool above, we’ll use IP address range 192.168.10.100 – 200. By default all traffic will be sent through the tunnel once the remote user is connected.

Full Answer

What is Cisco ASA remote access VPN?

Cisco ASA Remote Access VPN. The remote user requires the Cisco VPN client software on his/her computer, once the connection is established the user will receive a private IP address from the ASA and has access to the network. The Cisco VPN client is end-of-life and has been replaced by the Cisco Anyconnect Secure Mobility Client.

How does the ASA assign IP addresses to remote users?

The ASA will assign IP addresses to all remote users that connect with the anyconnect VPN client. We’ll configure a pool with IP addresses for this: Remote users will get an IP address from the pool above, we’ll use IP address range 192.168.10.100 – 200.

How do I connect to the ASA from another computer?

This allows remote users to connect to the ASA and access the remote network through an IPsec encrypted tunnel. The remote user requires the Cisco VPN client software on his/her computer, once the connection is established the user will receive a private IP address from the ASA and has access to the network.

How to use clientless WebVPN with Asa?

The clientless WebVPN method does not require a VPN client to be installed on the user’s computer. You just open your web browser, enter the IP address of the ASA and you will get access through a web portal. You only have limited access to a number of applications, for example: There is no full network access when you use clientless WebVPN.

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How do I allow VPN through Cisco firewall?

SolutionCreate a Static (One-To-One) NAT so that the ASA that has a private IP on its outside interface, (192.168. ... Allow UDP 500 (ISAKMP) from the ASA (1.1. ... Allow UDP 4500 (NAT-TRAVERSAL) from the ASA (1.1. ... Allow UDP 500 (ISAKMP) from the ASA (192.168. ... Allow UDP 4500 (NAT-TRAVERSAL) from the ASA (192.168.

How configure NAT Cisco ASA firewall?

There are four steps involved in enabling static NAT:Create the network object and static NAT statement. ... Create a NAT statement identifying the outside interface. ... Build the Access-Control List. ... Apply the ACL to the outside interface using the Access-Group command: access-group OutsideToWebServer in interface outside.

What is NAT 0 in Cisco ASA?

NAT 0 basically used is to allow traffic between two firewall segment without address translation, or for VPN interesting traffic (vpn via PX) where you bypass address translation to allow local internal segment to talk to other/remote segment.

What is source NAT and destination NAT in ASA?

Destination NAT enables the translation of one destination address to another, a destination address and port to another destination address and port, or a group of destination addresses to another group of equal size. Source NAT is the translation of source IP addresses and TCP/UDP ports in the headers of IP flows.

What is policy NAT in Cisco ASA?

A Policy NAT is any translation that occurs based upon matching both the Source and Destination of traffic. A Twice NAT is any translation that involves translating both the Source and Destination of traffic.

What is ip nat inside source static?

This is the difference between the two commands: ip nat inside source: Translates the source IP address of packets that travel from inside to outside. Translates the destination IP address of packets that travel from outside to inside.

How NAT works in ASA firewall?

Network Address Translation is used for the translation of private IP addresses into public IP addresses while accessing the internet. NAT generally operates on a router or firewall. In this type of NAT, multiple private IP addresses are mapped to a pool of public IP addresses.

What are different types of NAT in Asa?

Cisco ASA NAT – Contents:Static NAT.Static PAT.Dynamic PAT.Dynamic NAT.

What is difference between auto NAT and manual NAT in Asa?

An Auto-NAT rule only uses the source address and port when matching and translating. Manual NAT can match and translate source and destination addresses and ports. In both cases, the Translated Source may be the IP of the egress interface or an object. The PAT Pool option is available when using dynamic translations.

How do I configure no NAT?

Details. No NAT rules are configured (at Policies > NAT) by specifying the desired match conditions (zone, IP, etc.) and leaving the source translation and destination translation fields blank. It is also possible to specify a list of IP addresses or IP address ranges in a NAT rule.

How do I set up auto NAT?

Auto NAT is configured using the following steps: Create a network object. Within this object define the Real IP/Network to be translated....Configuring Dynamic NAT.Dynamic PAT (Hide NAT)Configuring Static NAT or Static NAT with Port Translation.

What is Destination NAT?

Destination NAT is the translation of the destination IP address of a packet entering the Juniper Networks device. Destination NAT is used to redirect traffic destined to a virtual host (identified by the original destination IP address) to the real host (identified by the translated destination IP address).

What are different types of NAT in Asa?

Cisco ASA NAT – Contents:Static NAT.Static PAT.Dynamic PAT.Dynamic NAT.

How do I configure no NAT?

Details. No NAT rules are configured (at Policies > NAT) by specifying the desired match conditions (zone, IP, etc.) and leaving the source translation and destination translation fields blank. It is also possible to specify a list of IP addresses or IP address ranges in a NAT rule.

What is the difference between NAT and PAT?

In NAT, Private IP addresses are translated into the public IP address. In PAT, Private IP addresses are translated into the public IP address via Port numbers.

What is order of preference of NAT types in Cisco ASA?

If i remember correctly, the order for object nat rules is:prefer static object nat rules over dynamic object nat rules. ... prefer "more specic objects" (objects containing less ip addresses) ... prefer "objects containing the lowest ip address" ... object nat rules in "alphabetical order of object names"

How many interfaces does an ASA have?

The ASA has two interfaces: inside and outside. Imagine the outside interface is connected to the Internet where a remote user wants to connect to the ASA. On the inside we find R1, I will only use this router so the remote user has something to connect to on the inside network. Let’s look at the configuration!

What is VPN_POLICY?

The group policy is called VPN_POLICY and it’s an internal group policy which means it is created locally on the ASA. You can also specify an external group policy on a RADIUS server. I added some attributes, for example a DNS server and an idle timeout (15 minutes). Split tunneling is optional but I added it to show you how to use it, it refers to the access-list we created earlier.

Does Cisco VPN require ASA?

The remote user requires the Cisco VP N client software on his/her computer, once the connection is established the user will receive a private IP address from the ASA and has access to the network .

Can remote VPN users access certain networks?

If you want to configure an access-list so the remote VPN users can only reach certain networks , IP addresses or ports then you can apply this under the group policy.

Can you use VPN on remote network?

If you don’t want this then you can enable split tunneling. With split tunneling enabled, we will use the VPN only for access to the remote network. Here’s how to enable it:

Introduction

This document describes how to configure the Cisco 5500 Series Adaptive Security Appliance (ASA) to act as a remote VPN server using the Adaptive Security Device Manager (ASDM) or CLI and NAT the Inbound VPN Client traffic.

Prerequisites

This document assumes that the ASA is fully operational and configured to allow the Cisco ASDM or CLI to make configuration changes. The ASA is also assumed to be configured for Outbound NAT. Refer to Allow Inside Hosts Access to Outside Networks with the use of PAT for more information on how to configure Outbound NAT.

Background Information

Remote access configurations provide secure remote access for Cisco VPN clients, such as mobile users. A remote access VPN lets remote users securely access centralized network resources. The Cisco VPN Client complies with the IPSec protocol and is specifically designed to work with the security appliance.

Configurations

Complete these steps in order to configure the Cisco ASA as a remote VPN server with ASDM:

Verify

Attempt to connect to the Cisco ASA through the Cisco VPN Client in order to verify that the ASA is successfully configured.

Troubleshoot

This section provides information you can use to troubleshoot your configuration.

What is the IP address of AnyConnect?

You can see that we received IP address 192.168.10.100 (the first IP address from the VPN pool). Anyconnect creates an additional interface, just like the legacy Cisco VPN client does.

What is AnyConnect VPN?

Anyconnect is the replacement for the old Cisco VPN client and supports SSL and IKEv2 IPsec. When it comes to SSL, the ASA offers two SSL VPN modes: Clientless WebVPN. AnyConnect VPN. The clientless WebVPN method does not require a VPN client to be installed on the user’s computer. You just open your web browser, ...

What happens when a VPN user terminates a session?

Normally when the remote VPN user terminates the session, the anyconnect installer will be uninstalled. The anyconnect keep-installer installed command leaves it installed on the user’s computer.

What happens when you have an inbound access list?

When you have an inbound access-list on the outside interface then all your decrypted traffic from the SSL WebVPN has to match the inbound access-list. You can either create some permit statements for the decrypted traffic or you can just tell the ASA to let this traffic bypass the access-list:

Why does my client tries to download AnyConnect?

The client tries to download the Anyconnect automatically, this is because of the anyconnect ask none default anyconnect command that we used. Since we are using a self-signed certificate you will get the following error message:

When remote users connect to our WebVPN, do they have to use HTTPS?

The following option is not required but useful, whenever someone accesses the ASA through HTTP then they will be redirected to HTTPS:

What is an ayconnECT_policy?

The group policy is called “ANYCONNECT_POLICY” and it’s an internal group policy which means that we configure it locally on the ASA. An external group policy could be on a RADIUS server.

What is Cisco CLI Analyzer?

The Cisco CLI Analyzer ( registered customers only) supports certain show commands. Use the Cisco CLI Analyzer in order to view an analysis of show command output.

Why does VPN never work?

In overlapping scenarios, communication across the VPN never happens because the packets never leave the local subnet since the traffic is sent to an IP address of the same subnet.

When to use NAT or translation?

When the VPN protected networks overlap and the configuration can be modified on both endpoints; NAT can be used to translate the local network to a different subnet when going to the remote translated subnet.

When to create a manual statement to translate the local network to a different subnet?

Create a manual statement to translate the local network to a different subnet only when going to the remote subnet (also translated)

Does Cisco Adaptive Security Appliance have IP addresses?

Make sure you have configured the Cisco Adaptive Security Appliance with IP addresses on the interfaces, and have basic connectivity before you proceed with this configuration example.

What is remote access VPN?

In remote access VPN, you might want users on the remote networks to access the Internet through your device. However, because the remote users are entering your device on the same interface that faces the Internet (the outside interface), you need to bounce Internet traffic right back out of the outside interface. This technique is sometimes called hair pinning.

Where does remote access VPN problem originate?

Remote access VPN connection issues can originate in the client or in the Firepower Threat Defense device configuration. The following topics cover the main troubleshooting problems you might encounter.

How to view VPN configuration?

Click Device, then click View Configuration in the Site-to-Site VPN group.

How to use a VPN on a computer?

Step 1. Using a web browser, open https://ravpn-address , where ravpn-address is the IP address or hostname of the outside interface on which you are allowing VPN connections. You identify this interface when you configure the remote access VPN. The system prompts the user to log in. Step 2.

How to complete a VPN connection?

To complete a VPN connection, your users must install the AnyConnect client software. You can use your existing software distribution methods to install the software directly. Or, you can have users install the AnyConnect client directly from the Firepower Threat Defense device.

What is AnyConnect client profile?

AnyConnect client profiles are downloaded to clients along with the AnyConnect client software. These profiles define many client-related options, such as auto connect on startup and auto reconnect, and whether the end user is allowed to change the option from the AnyConnect client preferences and advanced settings.

How long is a VPN idle?

Idle Timeout —The length of time, in minutes, that the VPN connection can be idle before it is automatically closed, from 1-35791394. The default is 30 minutes. Browser Proxy During VPN Sessions —Whether proxies are used during a VPN session for Internet Explorer web browsers on Windows client devices.

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Introduction

Prerequisites

  • Requirements
    This document assumes that the ASA is fully operational and configured to allow the Cisco ASDM or CLI to make configuration changes. The ASA is also assumed to be configured for Outbound NAT. Refer to Allow Inside Hosts Access to Outside Networks with the use of PATfor more infor…
  • Components Used
    The information in this document is based on these software and hardware versions: 1. Cisco Adaptive Security Appliance Software version 7.x and later 2. Adaptive Security Device Manager version 5.x and later 3. Cisco VPN Client version 4.x and later The information in this document …
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Background Information

  • Remote access configurations provide secure remote access for Cisco VPN clients, such as mobile users. A remote access VPN lets remote users securely access centralized network resources. The Cisco VPN Client complies with the IPSec protocol and is specifically designed to work with the security appliance. However, the security appliance can establish IPSec connectio…
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Configurations

  • Configure the ASA/PIX as a Remote VPN Server with ASDM
    Complete these steps in order to configure the Cisco ASA as a remote VPN server with ASDM: 1. Open your browser and enter https://<IP_Address of the interface of ASA that has been configured for ASDM Access> in order to access the ASDM on the ASA. Make sure to authorize any warning…
  • Configure the ASA/PIX to NAT Inbound VPN Client Traffic with ASDM
    Complete these steps in order to configure the Cisco ASA to NAT Inbound VPN Client traffic with ASDM: 1. Choose Configuration > Firewall > Nat Rules, and click Add. In the drop-down list, select Add Dynamic NAT Rule. 2. In the Add Dynamic NAT Rule window, choose Outside as the Interfac…
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Verify

  • Attempt to connect to the Cisco ASA through the Cisco VPN Client in order to verify that the ASA is successfully configured. 1. Click New. 2. Fill in the details of your new connection. The Host field must contain the IP address or hostname of the previously configured Cisco ASA. The Group Authentication information must correspond to that used in step 4. Click Savewhen you are finis…
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Troubleshoot

  • This section provides information you can use to troubleshoot your configuration. The Output Interpreter Tool (registered customers only) (OIT) supports certain show commands. Use the OIT to view an analysis of showcommand output. Refer to Most Common L2L and Remote Access IPSec VPN Troubleshooting Solutionsfor more information on how to troubleshoot Site-Site VPN.
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Related Information

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