Security Guide · Companion to Stage 1

Fixed-IP Secure Access.

Once Stage 1 is implemented, a simple way to ensure access as an entityOS space administrator is to set up access via a dedicated IP address. The same idea scales from one administrator to a whole team working in the field.

Dedicated-IP VPN Corporate VPN Egress EC2 + Elastic IP Browser Isolation Defence in Depth
The Core Idea

Ensure access to entityOS Cloud using a fixed IP address.

OPTION 01 Convenient Fixed IP

A VPN with a dedicated IP.

The simplest approach: use a VPN service that provides a dedicated IP address. The client runs on your local computer; once connected, your traffic is routed through the provider and appears to originate from a single assigned address you can allowlist everywhere.

Local Computer
encrypted VPN tunnel
VPN Provider
Dedicated Fixed IPthe allowlistable address
entityOS Cloud

e.g. Surfshark, NordVPN

Why it works well

  • Simple to deploy and relatively inexpensive.
  • Available from laptops and mobile devices.
  • Usable from different physical locations.
  • Compatible with your existing local applications.
The limitation

The local computer remains the security boundary. The same machine is often used for email, browsing, downloads, development and messaging — so a local compromise still sits alongside your admin access.

OPTION 02 Team & Field Access

A corporate VPN with a fixed egress IP.

The same idea, run for the organisation rather than one person. People in the field — on client sites, in vehicles, on hotel Wi‑Fi and mobile data — connect to a VPN you control. Wherever they happen to be, their traffic leaves through a single egress address you own, and that is the address you allowlist.

Field Deviceslaptops · phones · tablets
authenticated tunnel — SSO + MFA
Corporate VPN Gateway
controlled exit point
Fixed Egress IPthe allowlisted /32
entityOS Cloud

One address for the whole team — not one per person.

Why it suits people in the field

  • A single allowlist entry covers everyone, however many are travelling.
  • Behaves the same on client networks, hotel Wi‑Fi and mobile data.
  • Access follows identity — revoke the person, never the IP address.
  • Managed profiles push to phones and laptops through MDM.
  • Connection logs record who reached the system, from where and when.
The limitation

A corporate VPN answers where does this traffic come from for the whole organisation at once. It says nothing about the device behind it — a field laptop shared at home, running whatever, still arrives from the trusted address. It widens the set of machines standing behind one allowlisted entry, so pair it with device posture, phishing‑resistant MFA, and Option 03 for genuinely privileged administration.

Setting it up — the pattern

The technology varies; the shape does not. Seven decisions turn a VPN into an allowlistable egress point for a distributed team.

  1. 1

    Choose where the traffic leaves

    Terminate the tunnel somewhere you control a stable public address — a small network of your own with a hosting provider, an office edge with a static WAN address, or a VPN provider that assigns your organisation a dedicated one. Every other decision follows from this. Put it in the region closest to your field staff; every packet they send takes this detour.

  2. 2

    Reserve the address — and a second one

    Treat the egress address as infrastructure: reserve it, tag it as allowlisted, and make sure nothing releases it. Then stand up a second egress in a different location or zone and allowlist that too. With one address, a single failure locks out the entire field team at once.

  3. 3

    Anchor membership to identity

    Connect the VPN to your identity provider (SAML / OIDC, with SCIM for provisioning) so joining or leaving the team grants or revokes tunnel access automatically, and require phishing‑resistant MFA to connect. The fixed IP proves where traffic comes from; identity proves who sent it. Field access needs both — and no shared account or shared key, ever.

  4. 4

    Decide split‑tunnel or full‑tunnel

    Full tunnel sends everything through the egress — simplest to reason about, heaviest on bandwidth, and least forgiving on a weak mobile link. Split tunnel routes only what matters (entityOS Cloud, admin consoles, internal apps) and lets the rest go direct. Split is usually right for field staff, but the route list then is a security control: a destination missing from it gets no protection at all.

  5. 5

    Allowlist the egress addresses

    Add each egress address as a /32 to your Stage 1 allowlist, and to any other firewall rules, storage policies and SaaS admin allowlists that should follow the same rule. Record who owns each entry and why it exists. If the gateway offers IPv6, either carry it through the same egress and allowlist the prefix or turn it off — a device that connects over IPv6 will not present the allowlisted v4 address.

  6. 6

    Push the configuration to devices

    Distribute a managed VPN profile through MDM rather than asking people to configure clients by hand: per‑device certificates or keys, and always‑on or on‑demand rules that bring the tunnel up automatically for the protected destinations. A profile a user cannot misconfigure is one fewer support call from a job site with no signal.

  7. 7

    Operate it

    Keep connection logs — who, when, from which network. Alert on any request to the protected systems arriving from an address other than your egress addresses; that is either a misconfigured device or someone else. Review membership on a schedule, and keep a documented, tested break‑glass path for the day the egress itself is unreachable.

Plan for the day the address changes

Once a team depends on one allowlisted address, that address is a single point of failure. Change it by adding the new entry, migrating, then removing the old one — never the other way round — and keep at least two egress addresses live at all times.

Four ways to implement it

All four produce the same result — a stable address you can allowlist. They differ in who runs the gateway, how much infrastructure you own, and how quickly you can put it in a field worker’s hands.

CHOICE 01

Managed cloud VPN service

A VPN endpoint inside your own cloud account — AWS Client VPN being the obvious fit here. Associate the endpoint with a private subnet whose default route points at a NAT gateway holding an Elastic IP; that Elastic IP becomes the egress. Users federate through SAML, devices get a downloadable profile.

egress = NAT gateway Elastic IP

Billed per endpoint‑hour and per connection‑hour, plus NAT gateway and data charges — model it against team size before committing.

CHOICE 02

Self‑hosted WireGuard or OpenVPN

One small instance with an Elastic IP, running WireGuard or OpenVPN, with a keypair per device. The cheapest option and entirely under your control — the instance’s own address is the egress, and the whole configuration is a file you can read.

egress = instance Elastic IP

You own key distribution, patching and uptime. Comfortable for a handful of people; it becomes real administrative work past that.

CHOICE 03

Mesh network with an exit node

A zero‑trust mesh — Tailscale, NetBird and similar — where every device authenticates to your identity provider and there is no concentrator to size. Route the destinations that need the fixed address through an exit node or app connector running on an instance with a static IP.

egress = exit node static IP

The easiest rollout to phones and laptops in the field; the exit node is still one machine you must keep alive and patched.

CHOICE 04

Managed business VPN, dedicated IP

A per‑seat service — NordLayer, Twingate, Perimeter 81 and the like — that gives your organisation a dedicated gateway and address, with an admin console, SSO and device profiles included. No infrastructure to build or run.

egress = vendor‑assigned dedicated IP

Fastest to deploy. Confirm the address is genuinely dedicated to your organisation rather than shared, and that you can hold it long term.

Whichever you choose, the requirement entityOS sees is identical: one address — ideally two — that you control, presented on every connection. Choose on operational fit, not on the protocol.

OPTION 03 Isolated Access

A dedicated cloud workstation.

Create a workstation in AWS with Amazon EC2 and assign it an Elastic IP. The Elastic IP gives you the same stable, allowlistable address — but the real gain is isolation. Privileged work happens inside a small, controlled environment that is separate from your everyday computing.

General Environment

Your everyday machine

  • Email & messaging
  • Social media & general browsing
  • Downloads & documents
  • Development & AI tools
  • Browser extensions
One browser holds sessions, cookies, OAuth tokens, passkeys and cached credentials — a large surface shared with admin access.
Privileged Environment

Dedicated cloud browser

  • AWS Console
  • Infrastructure administration
  • Sensitive applications
  • Separate credentials & sessions
  • Nothing else
Reached over secure remote access, exiting through a fixed Elastic IP into your protected systems. Conceptually a privileged access workstation (PAW).

A normal workstation is multi-purpose, which creates a broad attack surface. A dedicated cloud browser separates the browser used for administrator operations from the one used for everyday Internet activity — different purposes, different trust levels.

Setting it up — the basics

A minimal EC2 Ubuntu workstation behind a fixed Elastic IP. Six steps in the AWS console — CLI equivalents shown where they help.

  1. 1

    Launch an Ubuntu instance

    In EC2 → Launch instance, choose Ubuntu and a small type such as t3.small, in a public subnet. Under Advanced details → User data, add a short script that installs a lightweight desktop (XFCE) and the xrdp server, so the box is ready for Remote Desktop on first boot.

    #!/bin/bash apt-get update apt-get install -y xfce4 xfce4-goodies xrdp echo "xfce4-session" > /home/ubuntu/.xsession chown ubuntu:ubuntu /home/ubuntu/.xsession systemctl enable --now xrdp

    Attach an IAM role with the AmazonSSMManagedInstanceCore policy so you can manage the box through SSM Session Manager (step 6) without opening SSH. Ubuntu’s AWS images already run the SSM agent.

  2. 2

    Lock down the security group

    Allow inbound only on RDP (3389) from your current address as a /32. Leave outbound open — that is the traffic which will carry the fixed IP.

  3. 3

    Allocate an Elastic IP

    In EC2 → Elastic IPs → Allocate. This reserves a stable public IPv4 address that stays yours.

    aws ec2 allocate-address --domain vpc
  4. 4

    Associate it with the instance

    Attach the address so all outbound traffic from the workstation leaves through this single fixed IP.

    aws ec2 associate-address --instance-id i-0abc… --allocation-id eipalloc-0abc…
  5. 5

    Allowlist the Elastic IP

    Add the Elastic IP as a /32 to your Stage 1 WAF IP Set, so entityOS admin access is permitted from the workstation and nowhere else.

  6. 6

    Set the login, connect — then stop when idle

    Once the instance is running (give the boot script a minute or two to finish), open SSM Session Manager and set the ubuntu user’s password — that becomes your Remote Desktop login. Session Manager runs in the browser over the SSM agent, so it needs no inbound SSH port.

    sudo passwd ubuntu

    Then open Microsoft Remote Desktop (or any RDP client), connect to the Elastic IP, and use the box as your dedicated browser environment. Stop the instance when finished; the Elastic IP stays allocated while it is stopped.

    Remote Desktop → <elastic-ip>:3389

AWS charges a small hourly fee for public IPv4 addresses — release the Elastic IP if you decommission the workstation.

Choosing an Approach

Three routes to a fixed IP.

All three give you a fixed outbound address that works while travelling. They solve different problems: convenient access for one person, one allowlistable address for a whole team in the field, or a genuinely isolated place from which to administer high-value systems.

Capability Dedicated-IP VPN Corporate VPN Egress EC2 + Elastic IP
Fixed outbound IPYesYesYes
Works while travellingYesYesYes
Scales to a teamPer seatExcellentLimited
Field & mobile devicesGoodExcellentPossible
Simple setupExcellentModerateModerate
Infrastructure to maintainNone / minimalGateway + egressEC2 instance
Central identity & revocationLimitedStrongGood
Connection audit trailLimitedStrongStrong
Local applicationsNativeNativeRemote
Browser isolationLimitedLimitedExcellent
Separate security boundaryLimitedLimitedStrong
Dedicated admin environmentNoNoYes
Suitable for everyday accessExcellentExcellentPossible
Suitable for privileged adminGoodGoodExcellent

Use a personal VPN where convenience is the priority, a corporate VPN where a distributed team needs one allowlistable address, and the cloud workstation where privileged access should occur from a controlled, separate environment. Most organisations end up running the second and the third together.

Defence in Depth

Controls that stack.

The cloud-workstation model lets several independent controls operate together. An attacker has to overcome each one in turn — not simply discover an Internet-accessible login page.

01 Strong AuthenticationPhishing-resistant MFA / passkeys for privileged accounts. Identity
02 Secure Remote AccessA controlled path to the cloud workstation — display and keyboard only. Access
03 Dedicated Cloud WorkstationA minimal EC2 environment holding only what admin work requires. Isolation
04 Dedicated BrowserPrivileged sessions and credentials kept entirely apart from everyday browsing. Surface
05 Fixed Egress IP + AllowlistA stable public address — Elastic IP or VPN egress — matched by AWS WAF IP Sets and security groups. Network
06 Application AuthenticationThe system's own login — the last gate on a sensitive resource. App

A fixed IP is an access-control signal. Layered with the controls above, it stops being a single wall and becomes one of several independent barriers an attacker must clear.

Hardening the Workstation

Additional controls.

A few practical measures that tighten the model further — most take minutes to apply.

MFA / Passkeys

Require phishing-resistant authentication for every privileged account.

Minimal Software

Install only what administrative work genuinely requires — nothing more.

Automatic Shutdown

Stop the EC2 workstation when idle — the Elastic IP stays allocated while it's off.

The Key Idea

Three levels of trust.

MODEL A

Convenient fixed-IP access

"Wherever I am, my computer should appear to come from the same IP address." Simple and effective for routine, lower-risk systems.

Laptop
Dedicated-IP VPN
↓ Fixed IP
↓ Allowlisted systems
MODEL B

Team fixed-IP access

"Wherever our people are working, the organisation should appear to come from one address we control." One allowlist entry, membership governed by identity.

Field devices
↓ SSO + MFA
Corporate VPN
↓ Fixed egress IP
↓ Allowlisted systems
MODEL C

Isolated privileged access

"Privileged access should occur from a controlled environment, separate from my everyday computing." A fixed identity and a separate execution environment.

Laptop
↓ Secure remote access
EC2 workstation
↓ Dedicated browser
↓ Elastic IP
↓ Allowlisted systems

Personal VPN — give the computer a trusted network location.

Corporate VPN — give the whole organisation one trusted network location, governed by identity.

Cloud workstation — create a trusted environment with a trusted network location.

The three are complementary rather than competing: a corporate VPN covers the day-to-day work of a distributed team, and the cloud workstation remains the stronger foundation for privileged activity — a dedicated place, not just a dedicated address.