Michel is right. This is a common configuration error: failing to have the mask 
agree on all interfaces. This is indeed what you would see.

 -mel

On Jun 25, 2019, at 4:07 PM, Michel Py 
<michel...@tsisemi.com<mailto:michel...@tsisemi.com>> wrote:

>  Scott wrote :
> No nothing like that. I'm just removing the .0/30 and 4/30 subnets and adding 
> .0/29.
> To  your previous question, yes .0 and .3 are unused. Once I change the 
> subnet .3
> becomes a usable IP and it's getting hammered with traffic, causing packet 
> loss.

You change the subnet mask on both sides, right ?

Looks to me like expected behavior. On the sending router, with a /30 mask the 
.3 address is not usable, so the sending router does not send traffic.
When you change to the /29 mask, .3 becomes usable, the sending router ARPs it, 
and starts sending traffic.

In a way, that is possibly good news, as it allows you do find out that you may 
have a DOS or a DDOS attack going on your .3 address.

Michel.



On 6/25/19 3:30 PM, Mel Beckman wrote:
> Also, what do you mean by “join to /30 public subnets to a /29”? You can’t 
> overlap subnets, if that’s what you’re thinking.
>
>  -mel
>
>> On Jun 25, 2019, at 3:27 PM, Mel Beckman 
>> <m...@beckman.org<mailto:m...@beckman.org>> wrote:
>>
>> You’re using just the two middle IPs in the four that make up the /30 set, 
>> right? IOW, the subnet x.x.x.0/30 should have .0 and .3 unused (they’re 
>> broadcast), and you use .1 and .2.
>>
>> -mel
>>
>>> On Jun 25, 2019, at 9:41 AM, Scott 
>>> <sc...@viviotech.net<mailto:sc...@viviotech.net>> wrote:
>>>
>>> First, sorry if this is a bit of a noob question.
>>>
>>> I'm trying to find a way of preventing a slew of traffic to an IP, or
>>> IP's, when I join two /30 public subnets to a /29. It appears that while
>>> the ranges are /30 someone is trying to brute-force the network and/or
>>> broadcast addresses for the ranges. When I change them to be a /29, now
>>> the router sees the traffic and starts dropping packets. Are there any
>>> suggestions for mitigating this behavior or is it just the nature of the
>>> beast?
>>>
>>> --
>>> 101010
>>>
>>>
--
101010

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