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''I wasn't trying to correct you in any way"
Peter, if I'm providing inaccurate information, anyone is welcome to correct, especially you!
"The difference between my and your understanding of the original poster's question is, I believe, in the fact that I have understood the original question as looking for a confirmation that the flooding of 255.255.255.255 across routers does not take place, while your answer seemed to gear more toward the ways to allow that flooding to happen."
I think, we both understand the OP's primary question. You, again, answered that so well (as also again, you usually do), nothing I could add to that.
However, the OP mentioned getting conflicting information. Conflicting information could be due to receiving inaccurate information, or it might be due to information received based on a slightly different variation of the question. For example, when OP wrote: "Will these packets be blocked or forwarded by default?" the simple answer is "they will be blocked by default".
The OP also wrote "Technically, these broadcast packets are not supposed to be forwarded through routers. However, I have been receiving conflicting information about this."
There's no question there, but the first statement is inaccurate unless you clarify conditions, i.e. "it depends". "By default" wasn't part of that statement, and we both agree a router can forward 255.255.255.255 broadcast packets. For example if it's configured for bridging, or using a L2TPv3 tunnel, or using MPLS XCONNECT. It can also "sort of" forward 255.255.255.255 if you consider conversion to a directed network broadcast. With such possibilities, I wondered if such may have been the cause or source of some of the "conflicting information".
So, yes, you're correct when you write ". . . your answer seemed to gear more toward the ways to allow that flooding to happen."
"I hope I have not offended you in any way." Certainly not!!!
My only concern is whether I've only confused the OP, while trying to be helpful.
To recap what Peter, I believe, and I are saying:
"Will these packets be blocked or forwarded by default?"
They will, by default, be blocked.
"Technically, these broadcast packets are not supposed to be forwarded through routers."
Technically, 255.255.255.255 might be forwarded through routers, but not by default, i.e. they need to be configured to do so.
"If these packets are forwarded, is there a way to block them?"
As a special configuration is configured to allow them, blocking all of them would be just not providing the special configuration.
"Should I look to block the ports these broadcasts are on anyway with some sort of ACL?"
If there is a special configuration to forward broadcasts, but you only wanted to forward some broadcasts, then yes, I believe, ACLs might be used to further restrict what broadcasts are forwarded. However, there may be other methods to control what broadcasts are forwarded. Peter's original post's information on IP helper-address and IP forward-protocol are such an example, although they also converted 255.255.255.255 to non-255.255.255.255 IP addresses.
