[Bloat] netperf server news

[Sebastian Moeller]

Dear Rich,

first, thanks for supplying that service.

> On Oct 6, 2020, at 12:52, Rich Brown <richb.hanover at gmail.com> wrote:
> 
> To the Bloat list,
> 
> I had some time, so I looked into what it might take to keep the netperf.bufferbloat.net server on-line in the face of an unwitting "DDoS" attack - automated scripts that run tests every 5 minutes 24x7. The problem was that these tests would blow through my 4TB/month bandwidth allocation in a few days.
> 
> In the past, I had been irregularly running a set of scripts to count incoming netperf connections and blacklist (in iptables) those whose counts were too high. This wasn't good enough: it wasn't keeping up with the tidal wave of connections.
> 
> Last week, I revised those scripts to work as a cron job. The current parameters are: run the script every hour; process the last two days' of kern.log files; look for > 500 connections; drop those addresses in iptables.
> 
> There are currently 479 addresses blacklisted in iptables (that explains why the bandwidth was being consumed so quickly). There are only a few new addresses being added per day, so it seems that we have flushed out most of the abusers.
> 
> My questions for this august group:
> 
> 1) The server at netperf.bufferbloat.net is up and running. I get full rate speed from my 7mbps DSL circuit, but that's not much of a test. I would be interested to hear your results.

From work:

bash-3.2$ ./betterspeedtest.sh
2020-10-06 14:46:19 Testing against netperf.bufferbloat.net (ipv4) with 5 simultaneous sessions while pinging gstatic.com (60 seconds in each direction)
.
 Download:  Mbps
  Latency: (in msec, 1 pings, 0.00% packet loss)
      Min: 6.868 
    10pct: 0.000 
   Median: 0.000 
      Avg: 6.868 
    90pct: 0.000 
      Max: 6.868
.............................................................
   Upload:  309.67 Mbps
  Latency: (in msec, 61 pings, 0.00% packet loss)
      Min: 6.644 
    10pct: 6.730 
   Median: 7.289 
      Avg: 7.385 
    90pct: 7.941 
      Max: 9.980
Press any key to continue...

bash-3.2$ ./betterspeedtest.sh
2020-10-06 14:49:33 Testing against netperf.bufferbloat.net (ipv4) with 5 simultaneous sessions while pinging gstatic.com (60 seconds in each direction)
................................................................................
 Download:  0 Mbps
  Latency: (in msec, 80 pings, 0.00% packet loss)
      Min: 6.583 
    10pct: 6.637 
   Median: 6.674 
      Avg: 6.694 
    90pct: 6.743 
      Max: 7.204
................................................................................
   Upload:  0 Mbps
  Latency: (in msec, 80 pings, 0.00% packet loss)
      Min: 6.555 
    10pct: 6.622 
   Median: 6.667 
      Avg: 6.687 
    90pct: 6.742 
      Max: 7.218
Press any key to continue...

So there seems to be an issue with the Download test, from home I currently get 0/0 for both Upload/download.... Maybe I just made it on the block list (not that I remember trying to reach that server in the last weeks at all).

Running flent's rrul_cs8 manually against netperf.bufferbloat.net gave me around 80/25 which seems  believable.


> 
> 2) The current threshold comes from this estimate: most speed tests use 10 connections: 5 connections up and 5 down. So 500 connections would permit about 50 tests over the course of two days. Is that enough for "real research"? (If you need more, I can add your address to my whitelist file...)

	I think 50 tests is quite generous, that is more than one test every hour for two days ;)

> 
> 3) I would be pleased to get comments on the set of scripts. I'm a newbie at iptables, so it wouldn't hurt to have someone else check the rules I devised. See the README at https://github.com/richb-hanover/netperfclean

	Outside of my area of expertise....

Best Reards
	Sebastian

> 
> Thanks.
> 
> Rich
> 
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