# Multicast Boundary Filtering

**URL:** <https://forum.networklessons.com/t/multicast-boundary-filtering/2781>\
**Category:** Lessons Discussion\
**Created:** [January 23, 2018, 12:40pm UTC](https://forum.networklessons.com/t/multicast-boundary-filtering/2781 "2018-01-23T12:40:06Z")\
**Posts on this page:** 1\
**Showing post:** 10

<div class="post-metadata">

**Author:** ![lagapidis](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/lagapidis/32/4949_2.png) [@lagapidis](https://forum.networklessons.com/u/lagapidis)\
**Post date:** [October 19, 2020, 5:30am UTC](https://forum.networklessons.com/t/multicast-boundary-filtering/2781/10 "2020-10-19T05:30:52Z")

</div>

Hello Gowthamraj

Whenever the 0.0.0.0 address is used in this context, it has a special meaning. This meaning can be seen in [RFC 5735](https://tools.ietf.org/html/rfc5735#page-3). Specifically, for this address it states the following:

```
   0.0.0.0/8 - Addresses in this block refer to source hosts on "this"
   network. Address 0.0.0.0/32 may be used as a source address for this
   host on this network; other addresses within 0.0.0.0/8 may be used to
   refer to specified hosts on this network.

```

Now in the case of the lesson, because the `host` keyword is being used, it is the 0.0.0.0/32 address that is specified. So in this case, this address is used as **the source address for this host on this network**.

So these particular entries allow multicast traffic destined to 239.1.1.1 and 239.2.2.2 that originate from the local device, namely R2.

I hope this has been helpful!

Laz

---

_[View the full topic](https://forum.networklessons.com/t/multicast-boundary-filtering/2781)._