HCDas> hello,

HCDas> is there any way to create a losspattern which only fires when there is
HCDas> loss on the last hops? Actually we are getting alot of false positive
HCDas> mails, because there is packetloss in the middle of the trace which 
doesnt
HCDas> bother anyone.

HCDas> thanks beforehand!


I'm not sure what you're talking about.
There's two situations I can envision that might match what you're saying. 
[But, as you'll see, it still doesn't make much sense.]

Option 1) There's packet loss in the "middle" of your connection somewhere - 
but there's nothing you can do about it since it's not in a network you have 
any control over. [I still expect you'd want to _know_ about it - so 
complaining about notices seems odd. On a side note: I don't send notices 
directly from smokeping. I use Nagios for *reporting* of smokeping events. It's 
not as fine grained as smokeping in the alert patterns, but it is a LOT better 
squelching, setting alert hours, and groups etc. Since I use Nagios for other 
monitoring tasks, it's a no brainer to use the smokeping plug-in and avoid 
using smokeping for alerts all together.]

Option 2) There's actually no packet loss, but if you do a trace-route one of 
the hops in the middle won't respond to you. As I understand this, this happens 
when a router is configured to give ICMP traffic low priority, and it's very 
heavily loaded. Thus, virtually all traffic IS being handled, but responses to 
low priority traffic like ICMP gets sporadically dropped. But this second case 
shouldn't show up in a standard FPING test. Further, it's a warning sign that 
something IS dropping traffic, even if it's "only" ICMP. [And, thus, I don't 
think it's a false-alarm. It's just an early warning that some traffic is being 
lost. And you'll probably find that latency sensitive, or packet-loss sensitive 
traffic IS affected - but you personally may not have a much or any of those 
types of traffic so you don't get complaints. My experience is that regular 
users probably won't complain until packet loss reaches >15%. But things like 
VPN tunnels and the like will run very badly in a 15% loss case. Browsing the 
web probably won't be noticeable enough to generate a complaint for must users.]

So, the question you pose is quite confusing.

I do have a setup in smokeping where certain triggers cause an MTR [Matts trace 
route - which is much like Window's Pathping.] This gives me the stats to 
evaluate exactly where the loss is, and it's nature so I can exert pressure on 
whomever needs to address the issue. And it prevents the vendor from weaseling 
out by claiming the loss is happening elsewhere outside their network. [Most 
effective on first or last hops, since we usually pay these vendors directly.]

So, clarify your situation - because I'm not at all sure I understand, or have 
offered anything of value.

-Greg
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