Please tell me the technician on the phone for my client was incorrect when he said that Meraki is incapable of doing address translation over an IPSec tunnel when the other side is not a meraki device……That is enough to make you want to throw your head into a wall. Not sure how a vendor could release hardware that is incapable of doing basic network functions like that.
Proxy auto-config (PAC) configuration
A proxy auto-config (PAC) file defines how web browsers can choose a proxy server for receiving HTTP content. PAC files include the FindProxyForURL(url, host) JavaScript function that returns a string with one or more access method specifications. These specifications cause the web browser to use a particular proxy server or to connect directly.
To configure PAC for explicit web proxy users, you can use the port that PAC traffic from client web browsers use to connect to the explicit web proxy. explicit web proxy users must configure their web browser’s PAC proxy settings to use the PAC port.
PAC File Content
You can edit the default PAC file from the web-based manager or use the following command to upload a custom PAC file:
config web-proxy explicit
set pac-file-server-status enable set pac-file-data <pac_file_str>
end
Where <pac_file_str> is the contents of the PAC file. Enter the PAC file text in quotes. You can copy the contents of a PAC text file and paste the contents into the CLI using this option. Enter the command followed by two sets of quotes then place the cursor between the quotes and paste the file content.
The maximum PAC file size is 256 kbytes. If your FortiGate unit is operating with multiple VDOMs each VDOM has its own PAC file. The total amount of FortiGate memory available to store all of these PAC files 2 MBytes. If this limit is reached you will not be able to load any additional PAC files.
You can use any PAC file syntax that is supported by your users’s browsers. The FortiGate unit does not parse the PAC file.
To use PAC, users must add an automatic proxy configuration URL (or PAC URL) to their web browser proxy configuration. The default FortiGate PAC file URL is:
http://:/
For example, if the interface with the explicit web proxy has IP address 172.20.120.122, the PAC port is the same as the default HTTP explicit web proxy port (8080) and the PAC file name is proxy.pac the PAC file URL would be:
http://172.20.120.122:8080/proxy.pac
From the CLI you can use the following command to display the PAC file URLs:
get web-proxy explicit
Explicit proxy firewall address types
Explicit proxy firewall address types improve granularity over header matching for explicit web proxy policies. You can enable this option using the Show in Address List button on the Address and Address Group New/Edit forms under Policy & Objects > Addresses.
The following address types are available:
The FortiGate explicit web proxy
You can use the FortiGate explicit web proxy to enable explicit proxying of IPv4 and IPv6 HTTP, and HTTPS traffic one or more FortiGate interfaces. The explicit web proxy also supports proxying FTP sessions from a web browser and proxy auto-config (PAC) to provide automatic proxy configurations for explicit web proxy users. From the CLI you can also configure the explicit web proxy to support SOCKS sessions from a web browser.
The explicit web and FTP proxies can be operating at the same time on the same or on different FortiGate interfaces.
If explicit web proxy options are not visible on the web-based manager, go to System > Feature Select and turn on Explicit Proxy.
In most cases you would configure the explicit web proxy for users on a network by enabling the explicit web proxy on the FortiGate interface connected to that network. Users on the network would configure their web browsers to use a proxy server for HTTP and HTTPS, FTP, or SOCKS and set the proxy server IP address to the IP address of the FortiGate interface connected to their network. Users could also enter the PAC URL into their web browser PAC configuration to automate their web proxy configuration using a PAC file stored on the FortiGate unit.
Enabling the explicit web proxy on an interface connected to the Internet is a security risk because anyone on the Internet who finds the proxy could use it to hide their source address.
If the FortiGate unit is operating in Transparent mode, users would configure their browsers to use a proxy server with the FortiGate management IP address.
If the FortiGate unit is operating with multiple VDOMs the explicit web proxy is configured for each VDOM. The web proxy receives web browser sessions to be proxied at FortiGate interfaces with the explicit web proxy enabled. The web proxy uses FortiGate routing to route sessions through the FortiGate unit to a destination interface. Before a session leaves the exiting interface, the explicit web proxy changes the source addresses of the session packets to the IP address of the exiting interface. When the FortiGate unit is operating in Transparent mode the explicit web proxy changes the source addresses to the management IP address. You can configure the explicit web proxy to keep the original client IP address. See Preventing the explicit web proxy from changing source addresses on page 2925.
For more information about explicit web proxy sessions, see Explicit web proxy sessions and user limits on page 2930.
FortiClient WAN optimization over IPsec VPN configuration example
This example shows how to add WAN optimization to a FortiClient IPsec VPN. The IPsec VPN tunnel allows remote FortiClient users to connect to the internal network behind the FortiGate unit.
Example FortiClient WAN optimization configuration
To configure the FortiGate unit
Because computers running FortiClient can have IP addresses that change often, it is usually not practical to add FortiClient peers to the FortiGate WAN optimization peer list. Instead, a FortiGate unit that accepts WAN optimization tunnel requests from FortiClient is usually configured to accept any peer. This example does this by adding a WAN optimization authentication group with Peer acceptance set to Accept Any Peer.
In addition this example includes a wanopt to internal policy to allow WAN optimization traffic reach the internal network. Finally passive WAN optimization is added to the ssl.root policy because WAN optimization is accepting traffic from the IPsec VPN tunnel.
1. Go to WAN Opt. & Cache > Authentication Groups and select Create New.
2. Configure the WAN optimization authentication group:
Name auth-fc
Authentication Method Certificate
Certificate Fortinet_Firmware
Peer Acceptance Accept Any Peer
3. Select OK.
4. Go to WAN Opt. & Cache > Profiles and select Create New (select the + button).
5. Add a profile for FortiClient WAN optimization sessions:
Name Fclient_Pro
Transparent Mode Select
Authentication Group auth-fc
Category Address
Address Name Internal-Server-Net
Type IP Range
Subnet / IP Range 192.168.10.0/24
Interface internal
9. Enter the following CLI command to add an explicit proxy policy to accept WAN optimization tunnel connections.
configure firewall explicit-proxy-policy edit 0
set proxy wanopt
set dstintf internal set srcaddr all
set dstaddr all set action accept set schedule always set service ALL
next end
To set up IPsec VPN to support WAN optimization
1. Go to VPN > IPsec Wizard, enter a Name for the IPsec VPN and select Dialup – FortiClient (Windows, Mac OS, Android).
2. Follow the wizard steps to configure the VPN. No special WAN optimization settings are required.
3. Go to Policy & Objects > IPv4 Policy and edit the policy created by the wizard.
This policy has the IPsec VPN interface created by the wizard as the source interface.
4. Turn on WAN Optimization and configure the following settings:
Enable WAN Optimization passive
Passive Option default
5. Select OK.
To configure FortiClient and start the WAN optimization SSL VPN connection
1. Open FortiClient, configure Advanced settings, and select Enable WAN optimization.
2. Add a new IPsec VPN connection.
Set the Server to the WAN1 IP address of the FortiGate unit (172.20.120.30 in this example).
No other settings are required for this example. You can add authentication in the form of a user name and password if required by the FortiGate unit.
3. Start the IPsec VPN tunnel.
You should be connected to the IPsec VPN tunnel and traffic in it should be optimized.
FortiClient WAN optimization
FortiClient WAN optimization supports protocol optimization and byte caching in IPsec VPN and SSL VPN tunnels between FortiClient and a FortiGate unit. To add WAN optimization to FortiClient, configure FortiClient Advanced settings and enable WAN optimization. This setting can then apply WAN optimization to any IPsec or SSL VPN tunnel between FortiClient and FortiGate, if the FortiGate IPsec or SSL VPN configuration also includes WAN optimization.
When FortiClient with WAN optimization enabled attempts to connect a server-side FortiGate unit, FortiClient automatically detects if WAN optimization has been added to the FortiGate tunnel configuration. If WAN optimization is detected and FortiClient can successfully negotiate with the FortiGate unit, WAN optimization starts.
FortiClient WAN optimization topology
Example reverse proxy web caching and SSL offloading for an Internet web server using a static one-to-one virtual IP
This section describes configuring SSL offloading for a reverse proxy web caching configuration using a static one-to-one firewall virtual IP (VIP). While the static one-to-one configuration described in this example is valid, its also common to change the destination port of the unencrypted HTTPS traffic to a commonly used HTTP port such as 8080 using a port forwarding virtual IP.
Network topology and assumptions
In this configuration, clients on the Internet use HTTP and HTTPS to browse to a web server that is behind a FortiGate unit. A policy added to the FortiGate unit forwards the HTTP traffic to the web server. The policy also offloads HTTPS decryption and encryption from the web server so the web server only sees HTTP traffic.
The FortiGate unit also caches HTTP and HTTPS pages from the web server so when users access cached pages the web server does not see the traffic. Replies to HTTPS sessions are encrypted by the FortiGate unit before returning to the clients.
In this configuration, the FortiGate unit is operating as a web cache in reverse proxy mode. Reverse proxy caches can be placed directly in front of a web server. Web caching on the FortiGate unit reduces the number of requests that the web server must handle, therefore leaving it free to process new requests that it has not serviced before.
Using a reverse proxy configuration:
When planning a reverse proxy implementation, the web server’s content should be written so that it is “cache aware” to take full advantage of the reverse proxy cache.
In reverse proxy mode, the FortiGate unit functions more like a web server for clients on the Internet. Replicated content is delivered from the proxy cache to the external client without exposing the web server or the private network residing safely behind the firewall.
In this example, the site URL translates to IP address 192.168.10.1, which is the port2 IP address of the FortiGate unit. The port2 interface is connected to the Internet.
This example assumes that all HTTP traffic uses port 80 and all HTTPS traffic uses port 443.
The FortiGate unit includes the web server CA and an SSL server configuration for IP address 172.10.20.30 and port to 443. The name of the file containing the CA is Rev_Proxy_Cert_1.crt.
The destination address of incoming HTTP and HTTPS sessions is translated to the IP address of the web server using a static one-to-one virtual IP that performs destination address translation (DNAT) for the HTTP packets. The DNAT translates the destination address of the packets from 192.168.10.1 to 172.10.20.30 but does not change the destination port number.
When the SSL server on the FortiGate unit decrypts the HTTPS packets their destination port is changed to port 80.
Reverse proxy web caching and SSL offloading for an Internet web server using static one-to-one virtual IPs
General configuration steps
This section breaks down the configuration for this example into smaller procedures. For best results, follow the procedures in the order given:
1. Configure the FortiGate unit as a reverse proxy web cache server.
2. Configure the FortiGate unit for SSL offloading of HTTPS traffic.
3. Add an SSL server to offload SSL encryption and decryption for the web server.
Also note that if you perform any additional actions between procedures, your configuration may have different results.
Configuration steps – web-based manager
To configure the FortiGate unit as a reverse proxy web cache server
1. Go to Policy & Objects > Virtual IPs and select Create New to add a static NAT virtual IP that translates destination IP addresses from 192.168.10.1 to 172.10.20.30 (and does not translate destination ports):
VIP Type IPv4 VIP
Name Reverse_proxy_VIP
Interface port2
Type Static NAT
Source Address Filter Do not select.
External IP Address/Range 192.168.10.1
Mapped IP Address/Range 172.10.20.30
Port Forwarding Do not select.
2. Select OK.
3. Go to Policy & Objects > IPv4 Policy and select Create New to add a port2 to port1 security policy that accepts HTTP and HTTPS traffic from the Internet.
Do not select security profiles. Set the destination address to the virtual IP. You do not have to enable NAT.
Incoming Interface port2
Source Address all
Outgoing Interface port1
Destination Address Reverse_proxy_VIP
Schedule always
Service HTTP HTTPS
Action ACCEPT
4. Turn on Web Cache.
5. Select OK.
6. From the CLI enter the following command to add HTTPS web caching to the security policy
Assume the index number of the policy is 5.
config firewall policy edit 5
set webcache-https ssl-server end
To configure the FortiGate unit to offload SSL encryption and cache HTTPS content
1. Go to System > Certificates and select Import to import the web server’s CA.
For Type, select Local Certificate. Select the Browse button to locate the file (example file name: Rev_Proxy_ Cert_1.crt).
The certificate key size must be 1024 or 2048 bits. 4096-bit keys are not supported.
2. Select OK to import the certificate.
3. From the CLI, enter the following command to add the SSL server and to add the server’s certificate to the SSL server.
The SSL server ip must match the destination address of the SSL traffic after being translated by the virtual IP (172.10.20.30) and the SSL server port must match the destination port of the SSL traffic (443). The SSL server operates in half mode since it performs a single-step conversion (HTTPS to HTTP or HTTP to HTTPS).
config wanopt ssl-server edit rev_proxy_server set ip 172.10.20.30
set port 443
set ssl-mode half
set ssl-cert Rev_Proxy_Cert_1
end
Configuration steps – CLI
To configure the FortiGate unit as a reverse proxy web cache server
1. Enter the following command to add a static NAT virtual IP that translates destination IP addresses from
192.168.10.1 to 172.10.20.30 (and does not translate destination ports):
config firewall vip
edit Reverse_proxy_VIP set extintf port2 set type static-nat
set extip 192.168.10.1
set mappedip 172.10.20.30 end
2. Enter the following command to add a port2 to port1 security policy that accepts HTTP and HTTPS traffic from the
Internet. Enable web caching and HTTPS web caching.
Do not select security profiles. Set the destination address to the virtual IP. You do not have to enable NAT.
config firewall policy edit 0
set srcintf port2 set srcaddr all set dstintf port1
set dstaddr Reverse_proxy_VIP
set schedule always
set service HTTP HTTPS
set action accept set webcache enable
set webcache-https ssl-server end
To add an SSL server to offload SSL encryption and decryption for the web server
1. Place a copy of the web server’s CA (file name Rev_Proxy_Cert_1.crt) in the root folder of a TFTP server.
2. Enter the following command to import the web server’s CA from a TFTP server. The IP address of the TFTP server is 10.31.101.30:
execute vpn certificate local import tftp Rev_Proxy_Cert_1.crt 10.31.101.30
The certificate key size must be 1024 or 2048 bits. 4096-bit keys are not supported.
3. From the CLI, enter the following command to add the SSL server.
The SSL server ip must match the destination address of the SSL traffic after being translated by the virtual IP (172.10.20.30) and the SSL server port must match the destination port of the SSL traffic (443). The SSL server operates in half mode since it performs a single-step conversion (HTTPS to HTTP or HTTP to HTTPS).
config wanopt ssl-server edit rev_proxy_server set ip 172.10.20.30
set port 443
set ssl-mode half
set ssl-cert Rev_Proxy_Cert_1 end
4. Configure other ssl-server settings that you may require for your configuration.
Monitoring Web caching performance
The web cache monitor shows the percentage of web cache requests that retrieved content from the cache (hits) and the percentage that did not receive content from the cache (misses). A higher the number of hits usually indicates that the web cache is being more effective at reducing WAN traffic.
The web cache monitor also shows a graph of web traffic on the WAN and LAN. A lower WAN line on the graph indicates the web cache is reducing traffic on the WAN. The web cache monitor also displays the total number of web requests processed by the web cache.
To view the web cache monitor, go to Monitor > Cache Monitor.
Web cache monitor
