Internet troubleshooting with MX68

[tantony]

Our Internet keeps going down every once in a while.  Of course, the ISP says everything looks fine on their side, and Meraki says they don't see anything either.  I didn't see anything in the Meraki's event log either.  I do see DoS attacks on our modem, but there's nothing we can do about that.  They said we could try changing our static IP.

When the Internet goes down, I can ping the Meraki's LAN IP, 10.1.10.4, but not Comcast's LAN gateway 10.1.10.1.  This usually happens after the modem does an automatic software update, but apparently, there's no way to stop the automatic update. 

I'm just wondering if anyone experienced anything similar?  Anything else I'm missing to check on the Meraki or on the modem?  We're supposed to get fiber soon, so I hope once that happens, everything will be normal.

[Nick]

I've seen something similar occur before a few times. We have usually traced it to the ISP's modem, funny you mention the auto updating as that was the route of a few of our issues as well.

When the issue occurs, can you access the wired.meraki.com page, does the MX report connection to the cloud? You can ping the Comcast modem as well, but you can't go any further? What does a trace route out show? Can you try pinging google.com and then 8.8.8.8 to rule out any form of DNS problems.

Is there anyway of getting a device in there to do a packet capture and find out what is going on?

[tantony]

When the issue occurs, I can access the wired.meraki.com page. It does not report connection to cloud. It says "something went wrong". I can ping our public IP, but not the LAN 10.1.10.1 on the modem. I can ping 10.1.10.4, which is the Meraki.

When the issue occurs, and I do a tracert, it goes out of the Meraki network, then times out. When the connection is back, it goes through the Meraki, then through the modem.

Am I missing something? The ISP already replaced the modem because of the same issue, but the new modem did a software update, and this started happening again.

[Nick · Accepted solution]

It does sounds to me like its the ISP modem. When it locks up you cannot ping 8.8.8.8 from the Meraki side? 

Is there a way you can remove the ISP modem from the equation? What is your internet presentation, RJ-11 or Cable? If its RJ-11 I would recommend trying one of theses, zero touch setup in most cases and you enter PPPoE details into the MX unit https://www.draytek.co.uk/products/business/vigor-130

It may be worth trying to move to a different static if you suspect a DOS is the cause of this though. Someone could be crashing the modem, but if it is still responding on the WAN I doubt that is the cause. Sorry to say but my suspect would most likely be that its a junk ISP modem again 😞 

[tantony]

Thank you, I think it's the modem / ISP, but I jsut want to make sure everything is correct on the Meraki side.  I opened  a case with Meraki, and they're also checking.

[Nick]

No problem 🙂  it does seem that way.

Do you have a spare box you could use in place of the MX to test if the issue persists? 

You could also move the MX over to another connection to test that if you have the means

[tantony]

I have another connection, but it's not that reliable.  I'm waiting for the USB modem to arrive as a backup.

We were using a Cisco 2900 router a few months ago with the same issue.

[Nick]

Let us know if you get to the route of it!

No pun intended... well sort of!

[tantony]

So I'm still having this issue.  I disabled advanced malware protection and content filtering.  Still same issue.

Called Meraki, they think it's a hardware issue.  They're sending me a replacement MX, should be here tomorrow.  

[Nick]

Right well fingers crossed then. Report back if you get this resolved with a hardware swap!

[tantony]

I don't have the new MX connected yet.  Still using the old Cisco router, and having same issue.  I noticed that if I connect a laptop to the modem and try to download a file using P2P application such as bittorrent, the modem looses internet connection.  

My modem is not in bridge mode, I'm thinking about putting it in bridge mode so the routing capabilities of the modem is turned off.

[tantony]

I’m not sure if anyone had this happen, but I noticed that if I unplug the router from the modem, and just connect a laptop to the modem, the laptop will not have internet if I use a peer to peer program such as BitTorrent.  I have a Comcast business modem. 

[Nick]

I have seen that before with cable modems.it could either be a useless modem or some form of block on the line. 

If its in routing mode does it still happen?

[tantony]

This is our third modem. This one is less than one month old. When you say routing mode, what’s does that mean?  Bridge mode is disabled on the modem. Should it be enabled?

[Nick]

I mean in terms of doing the NAT etc. If you have the modem in Bridge mode handing over a WAN IP to the MX then you have lightened the load as much as you can for the box