RE: Public Subnet re-assignments

[Michel Py <michel.py () tsisemi com>]

>  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 <mel () 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 <scott () 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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