Sprint filters

Mailman List Mirror (Read Only)
1

I have an organization which I allocated 147.237.0.0/16 from my country
block. They then wanted to subnet and hand out /24s and /23s to the
dozens of offices they have scattered thru the country and to allow each
office to connect to whatever ISP they wish. I told them that Sprint
would block the announcements of /24s and the like when coming from
147.237.0.0.

They said, then why does Sprint allow its customers to announce /24s from
their nets? They gave me as examples: 148.212.0.0 and 145.248.0.0.
I checked and sure enough here is what I found:

*>i148.212.1.0/24 192.121.156.41 100 0 1800 1239 1791
1292 i
*>i148.212.2.0/24 192.121.156.41 100 0 1800 1239 1791
1292 i
*>i148.212.3.0/24 192.121.156.41 100 0 1800 1239 1791
1292 i
*>i148.212.4.0/24 192.121.156.41 100 0 1800 1239 1791
1292 i
*>i148.212.5.0/24 192.121.156.41 100 0 1800 1239 1791
1292 i
*>i148.212.6.0/24 192.121.156.41 100 0 1800 1239 1791
1292 i
*>i148.212.7.0/24 192.121.156.41 100 0 1800 1239 1791
1292 i
*>i148.212.8.0/24 192.121.156.41 100 0 1800 1239 1791
1292 i
*>i148.212.9.0/24 192.121.156.41 100 0 1800 1239 1791
1292 i
*>i148.212.10.0/24 192.121.156.41 100 0 1800 1239 1791
1292 i
*>i148.212.11.0/24 192.121.156.41 100 0 1800 1239 1791
1292 i
*>i148.212.12.0/24 192.121.156.41 100 0 1800 1239 1791
1292 i
*>i148.212.13.0/24 192.121.156.41 100 0 1800 1239 1791
1292 i
*>i148.212.14.0/24 192.121.156.41 100 0 1800 1239 1791
1292 i
*>i148.212.15.0/24 192.121.156.41 100 0 1800 1239 1791
1292 i
*>i148.212.16.0/20 192.121.156.41 100 0 1800 1239 1791
1292 i
*>i148.212.32.0/20 192.121.156.41 100 0 1800 1239 1791
1292 i

I didn't have a good answer. Can anyone tell me what I should tell this
organization?

Thanks,
Hank

2

Sprint only applies the prefix length filters to external peers. All
of Sprint's external peers (as far as I know) peer with AS1239, and
the customers peer with other ASes (such as 1791). My best guess is
that AS1292 has transit from Sprint, which means they can announce
whatever they want into them.

Alec

3

Hank Nussbacher writes:

I have an organization which I allocated 147.237.0.0/16 from my country
block. They then wanted to subnet and hand out /24s and /23s to the
dozens of offices they have scattered thru the country and to allow each
office to connect to whatever ISP they wish. I told them that Sprint
would block the announcements of /24s and the like when coming from
147.237.0.0.

They said, then why does Sprint allow its customers to announce /24s from
their nets? They gave me as examples: 148.212.0.0 and 145.248.0.0.
I checked and sure enough here is what I found:

Sprint's customers pay them to announce their routes. If someone else
doesn't like it, they should filter - like AGIS has done.

-Hank

4

They said, then why does Sprint allow its customers to announce /24s from
their nets? They gave me as examples: 148.212.0.0 and 145.248.0.0.
I checked and sure enough here is what I found:

...

I didn't have a good answer. Can anyone tell me what I should tell this
organization?

That, among other things, Sprint is not the only NSP that filters.

randy