# OPNsense ###### guide-by-example ![logo](https://i.imgur.com/3ROLmaz.png) # Purpose Firewall, router, dhcp server, recursive DNS, VPN, traffic monitoring. * [Official site](https://opnsense.org/) * [GitHub](https://github.com/opnsense) * [Subreddits](https://www.reddit.com/r/opNsenseFirewall+opnsense/) Opensource.
Backend is FreeBSD with its packet filter `pf` and `configd` for managing daemons, services and templates.
For web gui it uses lighttpd web server, PHP/Phalcon framework and custom services built in Python. Can be installed on a physical server or in a virtual machine.

VMware ESXi

 This setup is running on the free version of ESXi 7.0 U3
#### Network setup Two physical network cards - NICs ![esxi-network](https://i.imgur.com/xvjyF3a.gif) * the default `vSwitch0` will be used for LAN side * create new virtual switch - `vSwitch1-WAN` * create new port group - `WAN Network`, assign to it `vSwitch1-WAN` #### Virtual machine creation * Guest OS family - Other * Guest OS version - FreeBSD 13 or later versions (64-bit) * CPU - 2 cores * RAM - 2GB, for basic functionality, later can assign more * SCSI Controller 0 - LSI Logic SAS * VM Options > Boot Options > Firmware - EFI Afterwards, edit the VM, add network adapter connected to `WAN Network` [Download](https://opnsense.org/download/) the latest opnsense - amd64, dvd, extract iso, upload to ESXi datastore, mount it in to the VMs dvd, check connect on boot #### OPNsense installation in VM Disconnect your current router and plug stuff in to the ESXi host. * let it boot up * login `root/opnsense` * set interfaces, in ESXi VM overview you can see networks and MAC addresses * set IPs, wan is usually left alone with dhcp,
static ip for LAN and enable dhcp server running and give it range * afterwards you should be able to access web gui * log out * log in as `installer/opnsense` * click through installation leaving stuff at default except for password * done After the initial setup, install plugin `os-vmware`
System > Firmware > Plugins
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Hyper-V

 Tested in windows 11 pro, v10.0.22621
#### Network setup Two physical network cards - NICs ![esxi-network](https://i.imgur.com/WnVQiZC.gif) * the Default Switch will not be used. * create new virtual switch - `WAN`
`external`, unchecked - *Allow management operating system to share this network adapter*
set correct physical NIC * create new virtual switch - `LAN`
`external`, set correct physical NIC
A cable with a live device at the end must be connected to LAN NIC for that LAN part of setup to start working. #### Virtual machine creation [Download](https://opnsense.org/download/) the latest opnsense - amd64, dvd, extract * generation 2 * firmware > security > turn off secure boot * SCSI Controller add DVD and mount opnsense iso * 2 cores, 2GB ram, for basic functionality, later can assign more * add two virtual NICs, assign WAN and LAN virtual switches * firmware boot order change * turn off automatic checkpoints * automatic stop action - shutdown Start the VM #### OPNsense installation in VM Disconnect your current router and plug stuff in to the ESXi host. * let it boot up * login `installer/opnsense` * click through the install process * UFS * disk * 8GB for swap * keep default password for now * set the interfaces, in hyperv you can check mac addresses * set IPs, wan is usually left alone with dhcp,
static ip for LAN and enable dhcp server running and give it range * afterwards you should be able to access web gui * log out * done No need to install some hyperv plugin after the installation, its included automaticly. **In case of disconnect of LAN side cable/switch, the hyperv host also loses connection**
Even if one might think it should work - WAN side is there, firewall is running, but it's the way hyperv external vswitches work. The physical NIC must be alive.
If the switch would be `internal` then it would be entirely virtual and independent of physical NIC state, but in host windows network connections, one cant bridge internal and external, switches nor NICs.
One way to solve this mild annoyance is to have external WAN, internal LAN1, and external LAN2. LAN1 and LAN2 would be [bridged in opnsense](https://docs.opnsense.org/manual/how-tos/lan_bridge.html). But seems this is rather cpu intensive and not recommended.
So I guess its living with this.
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First login and basics

 * click through wizzard, keep mostly defaults * hostname, DNS use 8.8.8.8 and/or 1.1.1.1 * timezone and ntp server * WAN - DHCP , defaults * LAN - set network and mask, I prefer 10.0.X.1 * root password * Update *
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Web GUI access from WAN side

 For example in cases where the only thing under protection of opnsense are some VMs on a hypervisor, but managment is easier done from the host.
Or if the risk is acceptabale,hoping random port, long password for a non-root user, and maybe some IP restrictios will be enough. - `pfctl -d` disables firewall and allows immediate web gui access on the WAN IP.
A restart of opnsense will always re-enable packet filtering - Disable `Block private networks` in `Interfaces: [WAN]`. - Set up a firewall rule that allows WAN traffic in `Firewall: Rules: WAN`
Add new rule; everything is left default except the `Destination` is set to `This Firewall`.
Can also enable `Log packets that are handled by this rule` if use of this rule should be visible in `Firewall: Log Files: Live View`. - Turn on `Disable reply-to` in `Firewall: Settings: Advanced`,
otherwise connections made from the same network will not get through.
Some [read on this.](https://forum.opnsense.org/index.php?topic=15900.0) - Reboot.
Afterwards opnsense should be accessible on WAN IP, without the need for `pfctl -d`. For some harderining of security. * Change the default web gui port in `System: Settings: Administration`.
From `443` to something random in range of 1024-65k, something like 32179.
Afterwards to access opnsense the port must be added to the url `:32179` * Turn off `HTTP Redirect` in `System: Settings: Administration`.
This only allows https encrypted communication. * Create a new user; add to administrators; disable `root` user in `System: Access: Users`.
Brute forcing username and password is more difficult than brute force password for a known user `root`. * Adjust the firewall WAN rule to be more restrictive.
Instead of `source` being `any`, setting a specific single machine IP.
Either right in the rule with `Single host or Network` and `192.168.1.200/32`,
or setting up an alias in `Firewall: Aliases`, setting IP in the `Content` field
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Port fowarding and NAT reflection(hairpin/loopback)

 [source](https://forum.opnsense.org/index.php?topic=8783.0) ### NAT reflection When you write `a.example.com` in to your browser, you are asking a DNS server for an IP address. When selfhosting that `a.example.com` it will give you your own public IP, and most consumer routers don't allow this loopback, where your requests should go out and then right back.
So a solution for above-consumer-level routers/firewalls is to just have checkboxes about NAT reflection, also called hairpin NAT or a NAT loopback. `Firewall: Settings: Advanced` - Reflection for port forwards: `Enabled` - Reflection for 1:1: `Disabled` - Automatic outbound NAT for Reflection: `Enabled` *extra info:*
Many consider NAT reflection to be a hack that should not be used.
That the correct way is split DNS, where you maintain separate DNS records for LAN side so that `a.example.com` points directly to some local ip. Reason being that machines on LAN that use FQDN to access other machine on LAN are not hitting the firewall with every traffic that goes between them. But IMO in small scale selfhosted setup its perfectly fine and it requires far less management. ### Port Forwarding: a host with IP 192.168.1.200, with port 3100 open TCP
want to port forward from the outside 3200 to 3100 - set up Aliases in `Firewall: Aliases`
- name: A short friendly name for the IP address you're aliasing. I'll call it "media-server" - type: Host(s) - Aliases: Input 192.168.1.200 - register the portforwarding in `Firewall: NAT: Port Forward`
- Interface: `WAN` - TCP/IP Version: `IPv4` - Protocol: `TCP` - Under `Source > Advanced`:
- Source / Invert: `Unchecked` - Source: `Any` - Source Port Range: `any to any` - Destination / Invert: `Unchecked` - Destination: `WAN address` - Destination Port range: `(other) 3200 to (other) 3200` - Redirect target IP: `Alias "media-server"` - Redirect target Port: `(other) 3100`
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Switch to https

 Not really needed. More like an exercise. But hey, its extra protection from someone snooping who is already on the LAN side I guess. ### on cloudflare * create dns record `fw.example.com` * get user ID - its in the url when you are on cloudflare dashboard, looks like 0122db3h3824893914169c9c4f919747f * in My Profile > Api Tokens > get Global API Key * in My Profile > Api Tokens > create token that looks [like this](https://i.imgur.com/pRelkUu.png) * zone/zone/read * zone/dns/edit * include all zones ### in opnsense acme plugin * download acme plugin * Services: ACME Client: Accounts - create account with your email where notifications about certs can go * Services: ACME Client: Challenge Types - create new dns challange with info you gathered from cloudflare, looks something [like this](https://i.imgur.com/bYZ6pTj.png) * Services: ACME Client: Certificates - create new certificate, stuff is just picked from the drop down menus, [looks like this](https://i.imgur.com/MC1kBCV.png) * now check logs if request went through on its own, or just click small icon to force renew the certificate, in logs in matter of a minute there should be some either success or fail ### in opnsense Services: Unbound DNS: General * add an override - so that the fw.example.com points to your local ip instead of going out, [looks like this](https://i.imgur.com/vqT9t3Y.png) ### in opnsense System: Settings: Administration * Alternate Hostnames - add your fw.example.com * SSL Certificate - pick from dropdown menu your certificate * apply changes * switch radio buttons at the top from http to https if its not already.
The previous steps should be done as opnsense will want to reload gui ### automatic renewal * `Services: ACME Client: Settings` - click tab - `Update Schedule`
opens `System: Settings: Cron` where renewal schedule in cron format is set
* everything is left default, only changing hours=`3` and months=`*/2`
this sets schedule to every other month at 3 after midnight. * cant tell yet if its working or not, got to wait few months and check now from local LAN side one can access web gui with https://fw.example.com and its an encrypted communication between the browser and the firewall
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Geoblock

 Lock out the entire world from your network, except for your own country. Great security benefits, but if you dont use dns challenge you might have issues with https certificates renewal and other stuff that initiates connection from the outside. Following [the official documentation](https://docs.opnsense.org/manual/how-tos/maxmind_geo_ip.html) ### on maxmind.com * register account on [maxmind.com](https://www.maxmind.com/en/geolite2/signup), this will give access to info which IP ranges belong to which country * in the freshly created maxmind account generate new license * in this url replace `My_License_key` with your actual license key
`https://download.maxmind.com/app/geoip_download?edition_id=GeoLite2-Country-CSV&license_key=My_License_key&suffix=zip` * paste it in browser, if its working it should download zip file with the IP info ### in opnsense * Firewall: Aliases: GeoIP tab - paste the url, click apply * switch to Aliases tab, create new geoip alias and select your own country
[something like this](https://i.imgur.com/vu2slRd.png) * Firewall: Rules: WAN - create new rule
block; source invert; source geoip alias we created; enable log packets that are handled by this rule; add description
[something like this](https://i.imgur.com/qi7sL9J.png) Observe it in action in Firewall: Log Files: Live View If you host anything with a website you can test if its working by using opera build in vpn, or by using some [online web site testers](https://www.webpagetest.org/). Assuming you are not in the country from which these run their test.
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Monitoring

 ### live view of connections Firewall: Log Files: Live View
Great tool to investigate settings and behavior with it's filter and autorefresh on/off and up to 20k last entries * checking out a specific firewall rule latest use
`label` `contains` `some string from the rules description`
* targeting specific ip on the LAN, for example docker host
`dst` `is` `192.168.19.200`
or ip address of a reverse proxy in docker, for me it was `10.36.44.8` * or specific port, like for minecraft port is 25565 * controlling for direction and understanding the concept - 🡪 IN means in to a firewall, 🡨 OUT means out of a firewall - the interfaces WAN/LAN, give the meaning to these IN/OUT directions - IN on LAN interface means traffic is leaving LAN and heading out through firewall - IN on WAN interface means traffic is coming in to - OUT on LAN means its leaving firewall and heading to LAN - OUT on WAN means its leaving firewall and heading to the WAN side
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Plugins

 * os-vnstat to have some general idea about traffic
--- --- ### Extra info and encountered issues * Health check - `System: Firmware` Run an audit button, Health * zenarmor that was disabled caused an error notification
opnsense and PHP Startup: Unable to load dynamic library 'mongodb.so'