A small business for which I am the system administrator has been experiencing intermittent internet dropouts. There seems to be no pattern to the dropouts — sometimes there is nothing for a week, and other times it will drop out dozens of times in a single day.
I have been running mtr (my traceroute) to try to diagnose the issue. I am including the mtr results below, pinging Google's Public DNS. I have also been running a test within the LAN, which shows exactly zero packets dropped, even over the course of a week or more; this leads me to believe the problem lies beyond our router. Everything is connected by gigabit ethernet. 10.0.0.1 is the LAN address our router, and the next hop (Time Warner's server) is where the packet loss begins.
Packets Pings
Host Loss% Drop Snt Last Avg Best Wrst StDev
1. 10.0.0.1 0.0% 0 10722 0.4 0.3 0.2 10.6 0.8
2. ##.###.##.## 7.9% 845 10722 22.1 21.7 7.7 292.0 14.2
3. ##.###.##.## 7.9% 845 10722 13.8 20.2 8.4 459.2 13.2
4. ##.###.##.## 7.9% 847 10722 22.3 22.0 8.9 374.5 13.2
5. ##.###.##.## 7.9% 852 10722 29.1 24.7 10.4 290.1 13.4
6. ##.###.##.## 7.9% 848 10722 23.3 25.2 8.3 643.9 15.3
7. 66.109.6.163 7.9% 849 10722 15.1 23.3 9.0 554.9 17.2
8. 66.110.96.53 7.9% 848 10722 26.3 21.3 7.9 467.2 14.4
9. 72.14.195.232 7.9% 846 10721 28.0 21.9 8.9 402.2 14.7
10. ???
11. 108.170.238.201 7.9% 842 10721 19.1 21.8 8.8 498.9 14.5
12. 8.8.8.8 7.9% 844 10721 24.0 21.4 8.7 414.5 13.5
It very recently came to my attention that there is a second device connected to the modem via ethernet. I want to note that the modem is actually a wireless gateway, but it was put into bridge mode and we have confirmed that our router (an Apple AirPort Extreme AC) gets a proper WAN address and DNS servers. So, the gateway is effectively just a modem.
Here is our network topography:
Time Warner Business Modem
├── Mystery Device
└── Apple AirPort Extreme AC
├── Netgear Unmanaged Gigabit Switch 1
│ ├── Apple iMac 1
│ │ └── Canon Printer
│ ├── Apple iMac 2
│ ├── Apple iMac 3
│ └── HP Ubuntu Laptop
├── Netgear Unmanaged Gigabit Switch 2
│ ├── HP Ubuntu Desktop
│ ├── Brother Printer 1
│ └── Brother Printer 2
└── Apple iMac 4
I work remotely so have not been able to visit the office to inspect the situation myself. We have been in contact with Time Warner and they assert that their modem has had no signal issues for the past few months. Our issues started a few weeks ago, after several years of consistent connection.
The cable between the modem and router was just replaced to rule out a faulty connection between the two, but the issue persists.
The core of my question is this — if this is a typical TW Business Class modem, does it only have one IP address to assign? I don't believe we are paying for additional IPs and I assume we only get one by default. If so, are the two ethernet devices connected (AirPort and mystery device) in competition for that IP address? Or has it been assigned to the router permanently by its MAC address? Would such a competition yield the observed mtr results above, perhaps when that mystery device attempts to connect to the internet?
Any advice would be much appreciated. If you have any idea of how I can further isolate the variables, I am comfortable with UNIX tools. In the meantime I have instructed someone in the office to disconnect the mystery device, but it is difficult to determine whether or not the issue will be fixed by that alone because it is not always observable, sometimes for days at a time.
Update: The second ethernet cable coming out of the modem was not connected to anything, and has been unplugged. I assume that rules out a conflict in IP address assignment. Any other diagnostic ideas would be very much welcomed.
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