Two internet lines: keeping the office online when one fails
Is a second internet line worth it for your office? How to pick one that does not fail with the first, set up automatic failover, and test it.
The internet goes down at half past ten on a working morning. The accounting system stops loading, the IP phones go silent, and a quotation a client is waiting for sits in the outbox. Someone restarts the router, someone else opens a phone hotspot, and an hour later the line comes back.
A second internet line is the usual answer, but it helps only if it does not fail together with the first. This guide covers how to decide, what to ask for, and how to test the backup before you need it.
Why the internet drops, and what a second line cannot fix
Internet outages in Iraq have several causes:
- a fault in the provider's network;
- a cut cable between you and the provider;
- power loss at the provider's street equipment;
- government-ordered shutdowns on national exam mornings. In 2025 and 2026 these typically ran from about 6:00 to 8:00 in the morning, on exam days.
A second line protects you against the first three. It does nothing for the fourth, because an exam-morning shutdown affects all providers at once. Plan around those mornings: whatever a client expects first thing should go out the evening before, scheduled jobs such as backups should run outside those hours, and staff should know in advance.
Work out what an hour offline costs
With one line, all your work hangs on a single point of failure: one cable, one provider, one box on the wall. Before asking for quotes, write down three things:
- How many people cannot work without a connection, and what you pay them for that hour.
- The work that does not happen: orders not received, calls not answered, bookings not taken.
- How often the line failed in the last three months, and for how long. If nobody knows, start a log.
Put the result next to the monthly cost of a second line. A design studio working on local files may decide an outage is an inconvenience. A clinic that takes its bookings in an online system will reach the opposite answer quickly. If your number is small, a charged phone with a hotspot and a rule about who uses it may be enough, and you need not buy anything.
A real backup: a different provider and a different path
A backup must not share the things that make the main line fail. Two conditions together make it real:
- A different provider, so that a fault inside one company's network does not reach the other line.
- A different path or medium. If the main line is fibre in the ground, the backup should arrive another way: a wireless link from a tower, or a mobile-data line through a router with a SIM card.
Two lines from the same provider in the same cable fail together. So can two fibre lines from two companies if both cables enter the building through the same duct, because one excavator cuts both.
Automatic failover, tested every month
If switching lines means someone moving a cable by hand, the backup works only when that person is in the office. Let the router do it. A router with two internet ports (often sold as "dual-WAN") keeps checking whether the main line reaches the internet, moves traffic to the backup when it does not, and moves it back when the main line returns. The check should test an address on the internet, because in many outages the provider's box stays lit while nothing passes through it.
Then test it. Once a month, at a quiet time, unplug the main line and watch: does the office stay online, which services stop, and does traffic return when you plug the line back in? Untested backups fail for small reasons: a data plan that ran out, a subscription nobody renewed, a setting somebody changed.
What stops working on the backup line
On the backup, the office reaches the internet through another provider and appears to the outside world under a different address. Browsing, email, cloud systems and messaging carry on. Services that depend on a fixed address may stop:
- remote access to the office cameras;
- a VPN that connects the office to a branch;
- some IP phone setups.
Find these in the monthly test and decide what to do about each one.
The backup is usually the smaller line, so decide which traffic is allowed on it. If it is a mobile-data line with a limited allowance, one computer downloading updates can use it up. The router can be set to pass the accounting system, email and calls, and to hold back video, large backups and the guest Wi-Fi.
Power and alerts
Both lines pass through equipment that needs electricity: each provider's box, the router, and the switch that connects your computers. Plugged into an ordinary socket, they all go down with the first cut in the national power grid and stay down until the generator takes over and every device has restarted. Put them on a UPS, including the small box the provider installed, which is the one people forget. The same reasoning applies to software, as explained in power cuts are a design input.
Automatic failover hides the failure from your staff, and it can hide it from you too. If nobody is told, the office can run on the backup for weeks, and when the backup fails too you have no line at all. Set the router to email or message a named person when it switches to the backup, and make that person responsible for calling the main provider.
Questions to put to each provider
Ask these before you sign, for both lines, and ask for the answers in writing:
- Repair time. Within how many hours do you commit to repairing a failed line, and does that include Fridays and holidays?
- Dedicated or shared capacity. Is the capacity reserved for us, or shared with other subscribers in the area?
- Who to call. Which number reaches a person who can register the fault and send a technician?
- The route. Does the line share a cable, a pole or a tower with our other line?
Checklist: is our backup real?
- The two lines come from different providers, by different paths or media.
- The router switches between them automatically, in both directions.
- We unplugged the main line this month, the office stayed online, and we know which services stopped.
- The router, the switch and both provider boxes are on a UPS.
- A named person is alerted when the office runs on the backup.
- Everyone knows the plan for exam mornings.
If the internet is slow in some rooms and fine in others, a second line will not change it. That is a coverage problem inside the building, the subject of Wi-Fi that covers a building.
PearlFibers provides dedicated business internet and builds office networks, for offices, buildings and commercial sites only. The work starts with a site visit and a written survey report before any quote, and the survey works the same way on a network someone else built. To ask for one, send the site address and your team size through the contact page.