Broadband lost on one computer only

I had Vodafone home broadband for a few years that was fast & reliable. About ten months ago I switched to Pulse 8 and it's never been as good, but sometimes it's dreadful and I have sub 1mbps download speeds a couple times a week. Restarting the router always fixes it for a few days.

Today this happened again and my Mac mini was not connecting to any web page, yet my daughter's MacBook Pro in the next room was fine with good speeds. This has happened previously a few times, though usually the other way around and the wifi connection is always strong everywhere in the house.

Can anybody think of a possible reason for this or know of a way to troubleshot it? I am using a Vigor 130 modem and a TP-Link AC2300 router.

I have been on the point of changing ISP recently, due to general frustration, however it seems hard to blame Pulse 8 in this instance when one computer is fine and the other has sudden issues. This is an 80/20 fibre package and with Vodafone I was seeing 74mbps over wifi day or night with the same hardware.

To start with the basics - are they both running the latest firmware and is there any unusual/custom config in place?

When it next happens, can you ping the router IP?

I would consider disabling the "advanced" firewall functions on the router too - for example things like DoS protection. Not familiar with your model but these things have a tendancy to cause issues.

It is common for computers to report "no internet" or fail to display a web page if they fail to resolve a DNS request - so it is possible that the DHCP lease has expired and been reissued, but the DNS resolver address(es) hasn't been propagated.
If you try a ping to an address such as 1.1.1.1 when the computer doesn't connect to a web page and that works then it is likely something like this is the issue.

The modem is running the latest firmware version. I actually tried going back one firmware version on the router a few weeks ago, because I found a TP-Link forum thread saying there had been performance issues after the latest one was installed. From what I can tell both seem the same and I did wonder if it might just be badly written firmware causing issues.

There is no unusual configuration, though I was using Quad9 for DNS. Yesterday I tried changing that to Google, then today with CloudFlare and the speeds generally seem rather better, even hitting 73mbps today over wifi, however it's just one day, so I really need to see for longer. Those are the speeds I used to see regularly in the past with Vodafone or BT.

In general terms it's been less than wonderful since day one and rarely hits 60mbps. Often it would be a lot less, but as long as I could use Netflix etc without problems I tried not to become over zealous. On the days when it suddenly hits 1mbps though that is obviously unusable, so if/when it happens again I'll try pinging the router.

The really perplexing part is when it affects one computer, but not the other and restarting the router soon has me back to around 50mbps. I would say these massive slowdowns seem to happen about once a week and they last until I restart the router. Sometimes both computers are affected equally.

The router has three lots of security settings. A malicious content filter, an intrusion prevention system and an infected device quarantine. I know the intrusion prevention system is a pain in the neck for FTP transfers and needs to be disabled, however it was switched off the last time this was bad yesterday.

The Macs have iCloud relay enabled, however these issues were also apparent with the previous OS, which predates this feature. This only applies to Safari anyway and when the slowdown hits all browsers are impacted, so I don't think this has any relevance.

We were replying at exactly the same time and I wonder if having used Quad9 in the router for DNS may be part of the problem. I tried using Google DNS, then CloudFlare today and it's generally been a lot better. I'll need to try for longer though to establish if this is really fixed or just a coincidence.

I only started using Quad9 around the time I switched to Pulse8, so there may be a clue there, though Quad9 is generally well considered. From memory I think I have also tried it with the automatic ISP DNS a couple times and still seen poor performance.

I think the problem I've had is highlighted in this forum thread. The DOS protection is kicking in erroneously, but seems to be worst with the latest firmware version. TP-Link have never fixed this.

https://community.tp-link.com/en/home/forum/topic/25...

I have just switched them all off and I'll see if that helps.

1. What is the PHY WiFi network stats from both machines?
[Hold option key and click on the WiFi icon in the menu bar, take a summary or post a screenshot.]

- swap or reposition each machine with the other and check the WiFi stats again.

2. Have you speed tested by direct Ethernet cable connection from each machine to the router?