Bitmask for 224.0.0.0 in Martians PF table entry

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Bitmask for 224.0.0.0 in Martians PF table entry

Aham Brahmasmi
Hi,

What is the correct bitmask for the 224.0.0.0 Martian table entry in
pf.conf?

There are two bitmasks in two links on this page -
http://www.team-cymru.org/bogon-reference-http.html. /3 in the The Text
Bogon List, Aggregated and /4 in IPv4 Fullbogons. /3 is also present in
https://www.openbsd.org/faq/pf/example1.html.

I think it should be /3, but I am still learning pf.

Thanks.

Regards,
ab

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Re: Bitmask for 224.0.0.0 in Martians PF table entry

Mike Coddington
On Wed, Jan 10, 2018 at 07:55:53PM +0100, Aham Brahmasmi wrote:

> Hi,
>
> What is the correct bitmask for the 224.0.0.0 Martian table entry in
> pf.conf?
>
> There are two bitmasks in two links on this page -
> http://www.team-cymru.org/bogon-reference-http.html. /3 in the The Text
> Bogon List, Aggregated and /4 in IPv4 Fullbogons. /3 is also present in
> https://www.openbsd.org/faq/pf/example1.html.
>
> I think it should be /3, but I am still learning pf.

224.0.0.0/3 would include the 240.0.0.0/4 block as well. For what it's
worth, I use 224.0.0.0/3 myself.

--
Put your Nose to the Grindstone!
                -- Amalgamated Plastic Surgeons and Toolmakers, Ltd.

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Re: Bitmask for 224.0.0.0 in Martians PF table entry

Kapetanakis Giannis
In reply to this post by Aham Brahmasmi
On 10/01/18 20:55, Aham Brahmasmi wrote:

> Hi,
>
> What is the correct bitmask for the 224.0.0.0 Martian table entry in
> pf.conf?
>
> There are two bitmasks in two links on this page -
> http://www.team-cymru.org/bogon-reference-http.html. /3 in the The Text
> Bogon List, Aggregated and /4 in IPv4 Fullbogons. /3 is also present in
> https://www.openbsd.org/faq/pf/example1.html.
>
> I think it should be /3, but I am still learning pf.
>
> Thanks.
>
> Regards,
> ab
>

See here:
https://www.iana.org/assignments/ipv4-address-space/ipv4-address-space.xhtml
224/4 is the multicast allocation (224-239)
240/4 is for future use (240-255)

224/3 is both of the above

if you don't use multicast then 224/3 should be ok, otherwise 240/4

G
ps. for multicast specific see https://www.iana.org/assignments/multicast-addresses/multicast-addresses.xhtml

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Re: Bitmask for 224.0.0.0 in Martians PF table entry

Aham Brahmasmi
Thank you Kapetanakis Giannis and Mike Coddington for your helpful
replies. I will now use /3, since I do not think that I will use
multicast.

Regards,
ab