Lag spikes on WAN etho... is this a DOS attack??

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BigFNTarget
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Joined: 21 Jun 2020
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PostPosted: Sat Aug 08, 2020 0:46    Post subject: Lag spikes on WAN etho... is this a DOS attack?? Reply with quote
Hello everyone,

I'm running a new R7000 nighthawk, flashed to the 06-02-2020-r43324 version of dd wrt and a wired connection to a gigabit fiber connection.

I had zero issues up until about a week ago, when I started getting weird lag spikes while playing online games, specifically first person shooters, and went to investigate.

I noticed on the dd wrt bandwidth monitor that it was receiving huge inbound traffic spikes of upwards of 1-3gbit/s on the WAN eth0 port (which from my understanding is the throughput lane for all the network traffic).

Does this indicate a DOS attack on my system, or is this an issue with the router or the isp modem that is bridged?

Thanks in advance for any advice you can offer.

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Wildlion
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Joined: 24 May 2016
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PostPosted: Sat Aug 08, 2020 1:29    Post subject: Reply with quote
You do know that traffic is bursty, right? Most of the time you do not get a constant stream download, especially for things like video or system updates.

A DOS would want to be sustained.
BigFNTarget
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PostPosted: Sat Aug 08, 2020 1:53    Post subject: Reply with quote
Yes, but I have a 1gbit/s connection, and the incomming spikes are over 5gbit/s and the outgoing are 1gbit/s.

I am also not downloading anything and only have my phone connected to the router at the time of testing.

Does this not indicate an issue? It seems like maxxing out my connection, even for a split second, would cause me to experience lag in a game, like my packets are delayed in that time...

Are you saying that these kind of spikes in the bandwidth monitoring is normal?
msoengineer
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PostPosted: Sat Aug 08, 2020 3:18    Post subject: Reply with quote
you're not getting a D.o.S. attack, something on your LAN has bursty traffic and most likely several devices at the same time... none of it makes any sense because the ports on that router are only 1gbps and you are hitting 4gbps...so not humanly possible unless it's totaling all LAN traffic on all 4 ports...

Don't trust those graphs.

to fix your laggy games you need to use Q.o.S.
use HTB & PIE to start...

that router will die at 180-200mbps with qos on because it doesn't have enough cpu for gig speed AND qos...so pick your poison...low lag using qos and 200mps (200000kbps), or lag NO qos and gig speed....

You might be able to eek out a little more, but nothing more than 210-215mbps, so set your limits the right way. and only check the ACK box initially for TCP. the others boxes may have negative impacts on latency.

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kernel-panic69
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PostPosted: Sat Aug 08, 2020 6:49    Post subject: Reply with quote
If you are on gigabit fiber, invest in an x86-based router. You are kicking yourself in the nuts otherwise. And, as always, do not expect ethernet performance out of wireless. You's beating your head on a brick wall if you do.
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kooper2013
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Joined: 10 Jan 2013
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PostPosted: Sat Aug 08, 2020 10:30    Post subject: Reply with quote
I'm seeing 5...20Gbps spikes on eth0 (AC87, r43078, WAP) with a 50Mbps connection. 'In' is alwayss half of 'out'.
Nothing to worry, I suppose it is just a timing glitch when calculating the speed.

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thommy181
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PostPosted: Sat Aug 08, 2020 10:41    Post subject: Lag spikes on WAN etho... is this a DOS attack?? Reply with quote
Why you use that old DD-WRT build. In my opinion you should update this and make fresh configuration for your deevice.
kooper2013
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PostPosted: Sat Aug 08, 2020 11:06    Post subject: Re: Lag spikes on WAN etho... is this a DOS attack?? Reply with quote
thommy181 wrote:
Why you use that old DD-WRT build. In my opinion you should update this and make fresh configuration for your deevice.


I could not yet figure how to use Wireguard on newer builds, I think something is weird with the new settings for netmasks.

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thommy181
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PostPosted: Sat Aug 08, 2020 11:46    Post subject: Lag spikes on WAN etho... is this a DOS attack?? Reply with quote
Read this document: https://wiki.dd-wrt.com/wiki/index.php/Wireguard and try to configure wireguard. In my opinion you should put the same netmask as ISP (I'm use this solve). If you create big own local network you can put individual mask there. I think it's not necessary generally.
Wildlion
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PostPosted: Sat Aug 08, 2020 15:24    Post subject: Reply with quote
The WAN side is only seeing spikes of 5Mbits/sec or 0.625 Megabytes per second. This is nothing.

On the LAN side where you have devices that you are connecting (unless it is open) those are updates to the page.... I did happen to notice while I was watching mine that it does the same thing and the in/out display had absolute value large but negative


Edit:

Added image with error spike. Not possible since wireless is disabled. This exceeded the true ability or router so it is an error.



Error.png
 Description:
Not possible
 Filesize:  41.4 KB
 Viewed:  738 Time(s)

Error.png


BigFNTarget
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Joined: 21 Jun 2020
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PostPosted: Sun Aug 09, 2020 2:48    Post subject: Reply with quote
Ok so it's not just my router doing this, that's good to hear I guess.

Could this be solved by updating to a new version of dd wrt? Anyone know a stable newer release I could use for my R7000?
Wildlion
DD-WRT Guru


Joined: 24 May 2016
Posts: 915

PostPosted: Sun Aug 09, 2020 21:58    Post subject: Reply with quote
Can not promise that it will fix it, the screenshot is from 2020_07_23_build_43904

I do not have direct experience with R7000, so I can not tell you if it would help for other things.
Roger W
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PostPosted: Thu Sep 03, 2020 0:14    Post subject: Reply with quote
I just updated from a January build to current (44251) and started seeing the same graph spikes for the first time (only on my LAN interface, but at around 35 Gbit where there should just be background noise) , immediately. (search brought me to this thread) I think there's a regression in the measurement.

Asus RT-AC68U.
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