[FROG] disc0 interface in FreeBSD 12.x
Stephen Worley
sworley at cumulusnetworks.com
Thu Oct 1 18:45:29 UTC 2020
Can you not just blackhole it? `ip route *****/* blackhole`
As to why its allowed into the config... i'm not sure, it seems that was
intentionally allowed according to the patch.
On Thu, Oct 1, 2020 at 11:41 AM mike tancsa <mike at sentex.net> wrote:
> What is the preferred syntax going forward ? I just want to tie down
> larger prefixes to the discard interface so any packets sent to dead
> space just get discarded. I dont want icmp messages sent back.
>
> ip route 10.0.0.0/8 disc0 ?
>
> Also, if the old syntax is not going to work, perhaps not allow it in
> the config ?
>
> ---Mike
>
> On 10/1/2020 11:31 AM, Stephen Worley wrote:
> > this was disallowed starting
> > with https://github.com/FRRouting/frr/pull/4302
> >
> > If you have a valid use case might be worth discussing with the author
> > over slack.
> >
> > On Thu, Oct 1, 2020 at 9:33 AM mike tancsa <mike at sentex.net
> > <mailto:mike at sentex.net>> wrote:
> >
> > Hi Donald, the 10.128.128.144 is the disc0 interface on my production
> > router running frr6 and it works as expected. I setup another test
> box
> > with frr6 and used the same disc0 ip config
> >
> >
> > e.g. on frr6
> >
> > # ifconfig disc0
> > disc0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 65532
> > inet 10.128.128.1 netmask 0xfffffffc
> > groups: disc
> > nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
> >
> > frr6# sh ip route connected
> > Codes: K - kernel route, C - connected, S - static, R - RIP,
> > O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
> > T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
> > F - PBR,
> > > - selected route, * - FIB route
> >
> > C>* 10.128.128.0/30 <http://10.128.128.0/30> is directly
> > connected, disc0, 00:00:19
> >
> > frr6# sh ip route 10.128.128.1
> > Routing entry for 10.128.128.0/30 <http://10.128.128.0/30>
> > Known via "connected", distance 0, metric 1, best
> > Last update 00:00:42 ago
> > * directly connected, disc0
> >
> > frr6# conf t
> > frr6(config)# ip route 10.0.0.0/8 <http://10.0.0.0/8> 10.128.128.1
> > frr6(config)# ^Z
> > frr6# sh ip route 10.0.0.0/8 <http://10.0.0.0/8>
> > Routing entry for 10.0.0.0/8 <http://10.0.0.0/8>
> > Known via "static", distance 1, metric 0, best
> > Last update 00:00:06 ago
> > * 10.128.128.1, via disc0
> >
> > frr6#
> >
> >
> > on frr7
> >
> > frr7# sh ip route connected
> > Codes: K - kernel route, C - connected, S - static, R - RIP,
> > O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
> > T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
> > F - PBR, f - OpenFabric,
> > > - selected route, * - FIB route, q - queued route, r -
> > rejected
> > route
> >
> > C>* 10.128.128.0/30 <http://10.128.128.0/30> [0/1] is directly
> > connected, disc0, 00:24:49
> >
> > frr7# sh ip route 10.128.128.1
> > Routing entry for 10.128.128.0/30 <http://10.128.128.0/30>
> > Known via "connected", distance 0, metric 1, best
> > Last update 00:25:07 ago
> > * directly connected, disc0
> >
> > frr7# conf t
> > frr7(config)# ip route 10.0.0.0/8 <http://10.0.0.0/8> 10.128.128.1
> > % Warning!! Local connected address is configured as Gateway
> > IP(10.128.128.1)
> >
> > frr7# sh ip route 10.0.0.0/8 <http://10.0.0.0/8>
> > % Network not in table
> > frr7#
> >
> > ---Mike
> >
> >
> >
> > On 10/1/2020 8:00 AM, Donald Sharp wrote:
> > > Can we see the output of `show ip route 10.128.128.144` and `show
> ip
> > > route connected`?
> > >
> > > donald
> > >
> > > On Wed, Sep 30, 2020 at 3:03 PM mike tancsa <mike at sentex.net
> > <mailto:mike at sentex.net>> wrote:
> > >> Up to version 6.x of frr, I have been able to tie down larger
> > prefixes
> > >> with a static routing pointing to the discard interface on
> FreeBSD.
> > >>
> > >> eg. the static route entry
> > >>
> > >> ip route 10.0.0.0/8 <http://10.0.0.0/8> 10.128.128.144
> > >>
> > >> # sh ip route 10.0.0.0/8 <http://10.0.0.0/8>
> > >> Routing entry for 10.0.0.0/8 <http://10.0.0.0/8>
> > >> Known via "static", distance 1, metric 0, best
> > >> Last update 09w0d01h ago
> > >> * 10.128.128.144, via disc0
> > >>
> > >> where disc0 is
> > >>
> > >> # ifconfig disc0
> > >> disc0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu
> 65532
> > >> inet 10.128.128.144 netmask 0xfffffffc
> > >> inet6 fe80::1%disc0 prefixlen 64 scopeid 0x8
> > >> inet6 2001:db8::1 prefixlen 64
> > >> groups: disc
> > >> nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
> > >>
> > >>
> > >> however, on frr7.4 this no longer works,
> > >>
> > >> On my test box
> > >>
> > >> % ifconfig disc0
> > >> disc0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu
> 65532
> > >> inet 10.128.128.1 netmask 0xfffffffc
> > >> inet6 fe80::1%disc0 prefixlen 64 scopeid 0x6
> > >> groups: disc
> > >> nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
> > >>
> > >>
> > >>
> > >> i3# conf t
> > >> i3(config)# ip route 10.0.0.0/8 <http://10.0.0.0/8> 10.128.128.1
> > >> % Warning!! Local connected address is configured as Gateway
> > >> IP(10.128.128.1)
> > >> i3(config)#
> > >>
> > >> i3# sh ip route 10.0.0.0/8 <http://10.0.0.0/8>
> > >> % Network not in table
> > >> i3#
> > >>
> > >> If I user disc0, it seems to work, but I get warnings on start up
> > >>
> > >> i3(config)# ip route 10.0.0.0/8 <http://10.0.0.0/8> disc0
> > >>
> > >> i3# wr
> > >> Note: this version of vtysh never writes vtysh.conf
> > >> Building Configuration...
> > >> Configuration saved to /usr/local/etc/frr/zebra.conf
> > >> Configuration saved to /usr/local/etc/frr/bgpd.conf
> > >> Configuration saved to /usr/local/etc/frr/staticd.conf
> > >> i3# sh ip route 10.0.0.0/8 <http://10.0.0.0/8>
> > >> Routing entry for 10.0.0.0/8 <http://10.0.0.0/8>
> > >> Known via "static", distance 1, metric 0, best
> > >> Last update 00:00:07 ago
> > >> * directly connected, disc0, weight 1
> > >>
> > >> i3#
> > >>
> > >> 2020/09/30 14:57:53 STATIC: Static Route using disc0 interface not
> > >> installed because the interface does not exist in specified vrf
> > >> 2020/09/30 14:57:53 STATIC: Static Route using disc0 interface not
> > >> installed because the interface does not exist in specified vrf
> > >>
> > >> the kernel routing table does seem to have it installed
> > >>
> > >>
> > >> # netstat -nra | grep 10.0.0
> > >> 10.0.0.0/8 <http://10.0.0.0/8> disc0 U1
> > 0 65532 disc0
> > >> #
> > >>
> > >> What is the "proper" way to do this on frr7x ?
> > >>
> > >> Thanks
> > >>
> > >> ---Mike
> > >>
> > >>
> > >>
> > >>
> > >> _______________________________________________
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> > >> frog at lists.frrouting.org <mailto:frog at lists.frrouting.org>
> > >> https://lists.frrouting.org/listinfo/frog
> >
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> >
>
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