What you’re seeing
- The camera or DVR app works on the office Wi-Fi but times out from a phone on cellular data.
- Remote staff get "connection timed out" or "unable to reach server" when connecting to the office VPN or a hosted application.
- Online port-check tools report the port as closed even though a forwarding rule exists on the firewall.
- Access stopped working after the internet provider replaced the modem or changed the service.
Common causes
Every environment is different, but these are the causes our engineers find most often:
- The internet provider's modem is acting as a router too, creating double NAT so traffic never reaches the firewall where the forwarding rule lives.
- The connection uses carrier-grade NAT, meaning the office does not have a public IP address that outside traffic can reach.
- The forwarding rule points to an internal address that has since changed because the device picked up a new IP from DHCP.
- The public IP address changed and the DNS name or dynamic DNS entry still points to the old one.
- The internal device's own firewall, or a missing return route, drops the incoming connection even though the router passes it through.
- The provider blocks certain inbound ports on residential or basic business plans.
Why it matters
When a published service disappears, the people depending on it are usually outside the building: owners checking cameras after an alarm, staff connecting from home, or clients reaching a portal. Security footage that cannot be viewed remotely loses much of its value at exactly the moment it is needed. At the same time, hurried attempts to make it work by opening extra ports or turning on DMZ mode often leave a server or camera system exposed to constant internet scanning and attack.
How AskTechGurus fixes it
Skip the trial and error. A certified engineer works on your actual system, finds the root cause, and fixes it properly.
Tell us what’s happening
Submit a ticket in about two minutes. Paste the error, describe what changed, and pick your tier. No charge to submit.
A certified engineer diagnoses it
A vetted, US-based systems engineer claims your ticket, usually within minutes during business hours, and investigates over a secure remote session you can watch and end at any time.
Fixed and verified with you
The engineer resolves the root cause and confirms with you that it’s working. You don’t just get a workaround, and you get a plain-English summary of what was wrong.
Pay only when it’s resolved
Fixed price from $99, invoiced only after you approve the fix. If it isn’t resolved, you don’t pay.
Frequently asked questions
Is opening ports to the internet a security risk?
It can be. Every exposed service is visible to automated scanners, so we look at whether the port needs to be open at all or whether a safer option such as a VPN would do the job, and we explain the tradeoff before making changes.
Why did it break when nobody touched the firewall?
Changes outside the firewall are a frequent cause: a new modem from the provider, a changed public IP address or a device that received a new internal address. Pinpointing which link in the chain changed is the first thing we do.