HSRP via direct trunk or via L2 switch?

See example above

Would there be any different as to how HSRP should work if it would be connected via a direct Trunk or via a SW. I'm guessing not. In situation 3, Will R2 get the multicast from both the SW and R1 (directly over the trunk)? I think yes?

I guess Multicast, like broadcast is send out of all interface, or will the R1/R2 make a decision as to on which interface it will send out multicast/HSRP pakcets?

Is there a way to see if if HSRP message are received over an interface?

Find more posts tagged with

Comments

d4nz1g

debug condition interface Typex/y
debug standby packets

FrankGuthrie

d4nz1g wrote: »

debug condition interface Typex/y
debug standby packets

Are there no show command to show this? Debug command in production is always threading on thin ice.

636-555-3226

Unrelated, but since you're playing with HSRP anybody who's taken SANS SEC660 might suggest reading up on a related topic re: HSRP security

https://www.dshield.org/diary/Network%2BReliability,%2BPart%2B2%2B-%2BHSRP%2BAttacks%2Band%2BDefenses/10120

networker050184

There wouldn't be any difference in the behavior assuming your router supports L2 switching.

As far as the second part think STP here.

OctalDump

FrankGuthrie wrote: »

Are there no show command to show this? Debug command in production is always threading on thin ice.

This is why you try theoreticals and hypotheticals in the lab

But if HSRP is properly configured, there shouldn't be too much traffic to debug, and you'd only need to run it for a couple of minutes tops.

FrankGuthrie

networker050184 wrote: »

There wouldn't be any difference in the behavior assuming your router supports L2 switching.

Are you saying that a "pure" router doesn't support L2 switching? I know it does a layer 2 rewrite, but then again, decision are made on IP (Layer 3)

networker050184

In the pure sense, no a router doesn't switch. You'd need to front them with a switch for HSRP to function.

FrankGuthrie

networker050184 wrote: »

In the pure sense, no a router doesn't switch. You'd need to front them with a switch for HSRP to function.

And if there is a trunk between 2x L3? switches