> For the complete documentation index, see [llms.txt](https://jncia-workbook.gitbook.io/workbook/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://jncia-workbook.gitbook.io/workbook/junos-routing/2-null-routes.md).
# 2) Null Routes
### Pre-Work
Load the config called **null.routes.cfg** using the **load\_config\_on\_nodes.py** script.
```
python3 load_config_on_nodes.py --lab_dir three-routers --config_filename null.routes.cfg
```
### Lab
R1 has a static route for 200.200.200.200/32 via R2. Configure R2 so that it blackholes this traffic, and replies with an ICMP destination unreachable message.
```
admin@R1> ping 200.200.200.200
PING 200.200.200.200 (200.200.200.200): 56 data bytes
36 bytes from 10.1.2.2: Destination Net Unreachable
Vr HL TOS Len ID Flg off TTL Pro cks Src Dst
4 5 00 0054 df1c 0 0000 40 01 fdf9 10.1.2.1 200.200.200.200
36 bytes from 10.1.2.2: Destination Net Unreachable
Vr HL TOS Len ID Flg off TTL Pro cks Src Dst
4 5 00 0054 df47 0 0000 40 01 fdce 10.1.2.1 200.200.200.200
^C
--- 200.200.200.200 ping statistics ---
2 packets transmitted, 0 packets received, 100% packet loss
```
### Answer
Expand to reveal
```
set routing-options static route 200.200.200.200/32 reject
```
### Explanation
Expand to reveal
We have two options when creating a null route in Junos: we can use `discard` or `reject`. `Discard` will silently drop the packet. `Reject` will send an ICMP unreachable.
\
The null route is configured just like a normal static route, except the next-hop is `discard` or `reject` instead of an IP next-hop.
\
We can see the reject next-hop in the RIB:
```
admin@R2> show route protocol static
inet.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
200.200.200.200/32 *[Static/5] 00:00:04
Reject
```
\
As well as in the forwarding-table (`rjct`):
```
admin@R2> show route forwarding-table family inet destination 200.200.200.200
Routing table: default.inet
Internet:
Destination Type RtRef Next hop Type Index NhRef Netif
200.200.200.200/32 user 0 rjct 36 2
```
### Further Reading