FreeBSD 14.1 reports pack loss in mtr tool but not in the ping tool. Is my networking working properly?

antoniog120

antoniog120

FreeBSD 14.1 reports packet loss in mtr tool but not in the ping tool. Is my networking working properly? This is both for the domain google.com. Your feedback is appreciated.

Regards,

Antonio Gandara
 
Last edited:
antoniog120 said:
FreeBSD 14.1 reports pack loss in mtr tool but not in the ping tool.
Click to expand...
Intermediate routers might just drop packets that have an expired TTL instead of returning an "ICMP TTL time exceeded". It's also possible your ISP, or any of the network providers between you and the destination, have peering issues, and this causes the packet drops. So it depends on where exactly you are seeing those packet drops, it might be on a part of the internet you have no control over.

blog.apnic.net

How to properly interpret a traceroute or MTR | APNIC Blog

Guest Post: MTR is a useful tool for diagnosing packet loss.
blog.apnic.net blog.apnic.net
 
SirDice said:
Intermediate routers might just drop packets that have an expired TTL instead of returning an "ICMP TTL time exceeded". It's also possible your ISP, or any of the network providers between you and the destination, have peering issues, and this causes the packet drops. So it depends on where exactly you are seeing those packet drops, it might be on a part of the internet you have no control over.

blog.apnic.net

How to properly interpret a traceroute or MTR | APNIC Blog

Guest Post: MTR is a useful tool for diagnosing packet loss.
blog.apnic.net blog.apnic.net
Click to expand...
SirDice,

I have not seen anything in two tools the I used about "ICMP TTL time exceeded". You are saying that my ISP is having peering issues and that I have no control over this. Would the solution be just change ISP then?

Regards,

Antonio Gandara
 
antoniog120 said:
You are saying that my ISP is having peering issues
Click to expand...
No, I said it might be caused by peering issues, but it all depends on where and how you're seeing that packetloss in the mtr(8) output. Without actually seeing your output I cannot give you a definitive reason for the packetloss, you may just be misinterpreting the results.
 
SirDIce,

Here is the output you requested to see, Perhaps you can tell me what's going on with my network as all I am seeing is packetloss.

Regards,

Antonio Gandara
 

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SirDice,

Have you been to look at this image then provide me an understanding of what's going on with my network? I have not seen a reply form you in many days.

Regards,

Antonio Gandara
 
The four giving you a high number of packetloss are probably throttling the ICMP response. There's 0 packetloss for packets traveling all the way to the destination and back again. Thus there's nothing wrong with the connection. Read the article I posted, it's explained there.
 
SirDice said:
The four giving you a high number of packetloss are probably throttling the ICMP response. There's 0 packetloss for packets traveling all the way to the destination and back again. Thus there's nothing wrong with the connection. Read the article I posted, it's explained there.
Click to expand...
SIrDIce,

Thanks for your response. What article are you referring to and how do I read it?

Regards,

Antonio Gandara
 
twelve99 aka Arelion is a carrier, they have had occasional routing problems in the last few weeks and an outage in the london region last month that affected many routes in/out of europe.
If they really have a problem, there's really not much you can do on your end - changing the ISP won't help if its a global-scale carrier problem and you can be assured that if there's an actual problem, they'd know and work on it long before you even noticed it.

BUT:
The trace you are showing is absolutely fine.

Packet loss at intermediate hops is irrelevant if you still get a 'clean' route - i.e. all packages to and from the actual destination (or network) are coming through, as is the case in your mtr output.
In general, if the packet loss is only on single lines and doesn't propagate all the way to the bottom of the output, there is no problem - ICMP packet loss on some intermediate hops is usually expected, as those systems are rate-limited for ICMP replies (or TTL exceeded replies).
Read the article SirDice has linked, it also explains exactly these points:
The key thing that many people fail to understand about an MTR or traceroute is: Unless packet loss or increased RTT is seen on every hop between a given hop and the end of the trace, it is not a problem.
Click to expand...
 
Intermediate routers always rate limit ICMP. Why? Because it consumes CPU and there are millions of traces running through them daily
 
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Thanks for your responses!

I now have an idea what's going on with my network and the articles,/replies you posted is that this is normal output.

Regards,

Antonio Gandara
 
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