Network monitoring tool

we have the problem that there seem to be every now and then some network dropouts, potentially on the DSL side. The router logs do not mention anything.
So I wanted to get your input how this could be monitored efficiently…pinging a remote host is probably not the way to go.
Any ideas/proposals?

Wireless or ethernet connection?

If wireless, maybe look at the channel it’s on and possible interference, if the router channel is set to auto, then perhaps it’s switching so define the channel to use with least interference.

What is the router in question?

Hosts are connected via Ethernet, Router is a Fritzbox 7490, latest firmware applied

What chipset in use by the systems (could be drivers or firmware), check them all with;

/sbin/lspci -nnk |grep -A3 Ethernet

Not dropping DNS, if your using your ISP provided ones, look at using something like openDNS ( and in either the fritzbox or append to the system depending on if the are using wicked or NM.

Pick the system that’s used the most and setup wireshark to monitor and just filter on requests eg dns or keepalive broadcasts and may pickup where/when it’s occurring.

Setup a remote ping to say google every 15 seconds and check the icmp_seq numbers aren’t missed.

Use the ip command to monitor, eg;

ip --help

ip -o -t monitor

A standard procedure is to run tcpdump and then analyze the dump later with something like Wireshark.

But, that will only analyze tcp, and your problem could be something else.

SOP should be to complain to your Internet Provider and have someone inspect your line.
Particularly with DSL, line quality deteriorates rapidly the further you are from the telco office (max distance 1800 feet)
Also, since wires at the junction boxes are insulated by twisted pair (which sucks, it’s based on opposing EMF rather than real shielding), I’ve experienced problems when subscribers were connected to adjacent blocks or otherwise too close together.

Only <after> you’ve had your line inspected and evaluated, can you look for other causes.


Thanks for the hints guys!
Needless to say, I have already complained with Vodafone, and they had sent a technician (from Telekom owning the last mile) with the of course expected result that everything is fine!
In fact I dont need to monitor my PC, but somehow the connection between router and the outer world. The notifier of the outages is mainly my son when heavily gaiming (on this strange other OS)…so tcpdump is probably not the weapon of choice!

Does the router have the possibility to enable snmp or remote logging?

I see there are windows tools… maybe it would work under wine?

Your son’s complaints might be regular and reliable, but limited in information.

tcpdump will generate packet dumps which can be later analyzed for things like contention (something else running at the same time), specific types of packets which might be dropped, source/target for your dropped packets so that for instance if some remote endpoint is common to your packet drops, more. Wireshark can help, and I’ve even exported to a spreadsheet for that app’s simple visual sorting tools.

Depending on the type of game your son is playing, maybe the problem is in your system and not the network so it’d be helpful to shift some system resources from computing to networking, particularly if the game has peer-peer characteristics (massively large number of network connections). If that applies to you, then a paper I wrote a decade ago should still apply to all current openSUSE… How to increase and modify your networking buffers, modify your shifting TCP/IP windows, modify your TCP/IP Congestion Control algorithm, etc.