How to diagnose network issues?

[Exuraz]

Hi,

 

So, at home we have a network that has a modem, 2 routers (one router is on the DMZ-port of the other, to seperate the network from the business/firewalled side), 2 servers and a HomeAir wifi access point.

 

I don't know exactly how it is set up but I think one of the servers handles DHCP or DNS information for the router.

 

Since a couple of days ago, the connection is really slow to start up, while Speedtest gives a low ping of about 6ms and 100/100 Mb/s speeds. Pingtest also works fine and gives a good ping, except for that the package loss test fails because of a firewall? 

 

Sometimes the entire connection drops out, sometimes it works for a while.

Something that caught my attention is that when I experience the slow loading on my desktop that is connected to the DMZ-router, and when I restart the router, the entire router loses connection to the internet. Resetting just the router doesn't work, the entire network needs to be reset.

 

Sometimes the HomeAir (Connected to the main router that is directly after the modem) access point bugs out and refuses to give my phone internet with some IP problem. Other devices still work on the HomeAir, but yesterday the tablet had the same problem of not being able to connect. My dad thinks the issues are related to DHCP or DNS, but he can't find the problem.

 

 

Now, my question is:

Is there any way to scan the network and detect at what point the problem lies? 

 

Thanks in advance

 

 

 

[SkywardKkalox]

As starters, diagnosing networks can start from something simple to more advanced techniques later, as for your problem your HomeAir is an AP, your disconnects may be due to the high traffic of the channel, I suggest you switch to a lower channel 11 and down.

[MeshFile]

Isolation first to weed out possible scenarios.

 

I'll also assume your network is as follows:

Internet ---- modem --- [WAN] Router1 [LAN] ---------- [WAN] Router2 [LAN1] ------------ wired devices                               |   |                               |  [LAN2] ------ AP ))))))))) ((((((((( wireless devices                               +[LAN3] --------- Desktop

If it's not, indicate what is different.

 

You'll need to first test the modem. Directly wire computer to modem and nothing else. Check if packet loss is consistent upon multiple testings.

 

The next thing to isolate is if the problem is with the routers. Only have 1 router connected to the modem and devices you can test on.

Internet ---- modem --- [WAN] Router1                               |   |                               | [LAN2] ------ AP ))))))))) ((((((((( wireless devices                               +[LAN3] ------- Desktop

Observe if the issue persists on the Desktop and other wireless devices.

 

The rest will rely on how your network is actually setup. I can't post multiple scenarios just to hopefully guess your network.

[Exuraz]

As starters, diagnosing networks can start from something simple to more advanced techniques later, as for your problem your HomeAir is an AP, your disconnects may be due to the high traffic of the channel, I suggest you switch to a lower channel 11 and down.

 

Yeah we have alot of wireless things in our house, sonos, LG soundbar, headphones, tablet, phones, 2 wifi networks, etc.

 

 

Isolation first to weed out possible scenarios.

 

I'll also assume your network is as follows:

Internet ---- modem --- [WAN] Router1 [LAN] ---------- [WAN] Router2 [LAN1] ------------ wired devices                               |   |                               |  [LAN2] ------ AP ))))))))) ((((((((( wireless devices                               +[LAN3] --------- Desktop

If it's not, indicate what is different.

 

You'll need to first test the modem. Directly wire computer to modem and nothing else. Check if packet loss is consistent upon multiple testings.

 

The next thing to isolate is if the problem is with the routers. Only have 1 router connected to the modem and devices you can test on.

Internet ---- modem --- [WAN] Router1                               |   |                               | [LAN2] ------ AP ))))))))) ((((((((( wireless devices                               +[LAN3] ------- Desktop

Observe if the issue persists on the Desktop and other wireless devices.

 

The rest will rely on how your network is actually setup. I can't post multiple scenarios just to hopefully guess your network.

 

Yeah the setup is like that but I doubt there's actual package loss, it says there's a firewall that blocks the test while there shouldn't be any. 

[MeshFile]

Yeah the setup is like that but I doubt there's actual package loss, it says there's a firewall that blocks the test while there shouldn't be any. 

Some clarifications:

1. It's the speedtest.net test and it's the problem getting the packet loss results (not 'package loss') because of java?
2. When you say you need to reset the whole network, you mean actually resetting the routers to factory default and not just rebooting them?
3. When the issue where you need to 'reset the whole network' happens, what happened to the test on using your desktop computer directly wired to the modem? It's not getting online?

To observe packet loss, use a ping to google.com using (or other servers) using command 'ping google.com -t' and see if it has timeouts whenever your issue occurs.

[Exuraz]

Some clarifications:

1. It's the speedtest.net test and it's the problem getting the packet loss results (not 'package loss') because of java?
2. When you say you need to reset the whole network, you mean actually resetting the routers to factory default and not just rebooting them?
3. When the issue where you need to 'reset the whole network' happens, what happened to the test on using your desktop computer directly wired to the modem? It's not getting online?

To observe packet loss, use a ping to google.com using (or other servers) using command 'ping google.com -t' and see if it has timeouts whenever your issue occurs.

 

Yeah I guess the packet loss results are because of Java, but it shouldn't be since I have Java installed, both 64 and 32-bit.

When I mean resetting the network I mean rebooting everything.

I doubt there's packet loss, I think the problem here is that some element in the network is handled by a somewhat old server in the basement, but it should have been disabled now so I think it's fixed.

There were still some IP references to that server, and I think that's where it derped. 

 

Anyways, thanks for the help.