Got a CRS125-24G-1S router in my home, firmware 6.47.3, running a plain NAT router configuration. No queue’s nothing special. Just NAT and some firewall rules.
Recently (maybe since upgrading to 6.47.x??? Not sure), my internet connection speed drops into the single mbit range (this is on Ethernet - no Wifi). Rebooting the router always so far fixes it. There is plenty of memory (105MB free, cpu load is low and I see no other reason why the connection slows down so dramatically.
What can I do to troubleshoot this issues?
Are there any logs, resource counters or anything that I can/should be looking at?
Any know issues?
Happened again today
Really can’t figure out why. WAN speed drops from ~150mbit to single digits. Reboot fixes it 100% of the time.
No packet errors, no high resource consumption as far as I can tell, no spikes on the firewall rules etc.
Really don’t know how to debug this.
Any tips would be appreciated!
For now, downgraded firmware to the “Long term” tract. Doubt it’ll do anything, but hey…
In the meantime, keep the tips/tricks coming please.
The router isn’t currently in a bad state (though it’s only been a day since last reboot). If it’s back in slow mode, I’ll check the open connections. Hadn’t previously looked there yet.
Thanks for the hint. Will update once the router hicks up again.
To answer @xvo’s question:
Slowdown just happened again and WAN interface was still at 1 Gbps. I also disabled it and enabled it again and it came back up in 1 Gbps mode. Also did not resolve the issue.
Potential red herring:
At the last reboot about 2 days ago, I enabled syn-cookies. I had no real reason to do so, since there was nothing suspicious in the connection list, but I just gave it a try. To my surprise, the router made it two full days without the slowdown. Since I was curious, I disabled syn cookies again and a few hours later, the slowdown happened. Re-enabling syn-cookies on the fly did not resolve the issue.
But, as I said, this is a potential red herring, it may have been coincidence that the router stayed up a bit longer this time.
Nevertheless I have re-enabled syn-cookies and rebooted the router. As always, rebooting fixed the issue immediately.
Still no other idea what causes this. There are no TX/RX errors, the firewall isn’t going nuts, CPU/memory resource is low etc. Still don’t know where else to look.
Is rebooting the ISP router instead also solving the problem?
Seems like it is coming from the internet, but you have no tools to see it. A (root kit) hacked router will not show the offending traffic or heavy loaded resources. It will bypass any protection of your router. You could be a botnet victim. Rebooting brings you out of that loop, temporarily.
Only a device between the ISP router and the MKT can reveal that traffic.
First off, red herring is confirmed.
Less than one day with syn-cookies enabled and the router is slow again.
So that was a fliuke.
@bpwl, @xvo,
Thanks for those suggestions. I think I have another router somewhere, I’ll try to stick that between the CRS and the ISP.
I have no access to the ISPs router, so can’t reboot that.
For a general setup overview, this is simply my home router.
The setup is as following:
ISP → DOCSIS modem → CRS → LAN
