Talk:Null route

Adding null-route to Windows

>Can someone please put here how to create a null route on Windows using the route.exe >command? Bryan 04:00, 8 May 2006 (UTC)

Bryan, it's been a long time since you asked that question, but the easiest way to do this in windows is via the host file at %SystemRoot%\System32\drivers\etc\hosts. If you're looking to do this network wide, it is easier to do via firewalls and other network devices.

As far as the intent of the discussion of this page. Moving this topic into "blackholing" is a mistake as it is as problematic as the over use of the word "black hole", which should IMHO be renamed community wide to DNS redirection as that is what is happening.

Providing this type of routing information within that context is absolutely inappropriate, and not where a technician should be looking if he is interested in DNS redirection. This is a way to drop unwanted packets at an administrator's requirement, really something that should be placed into routing if it belongs anyplace, or perhaps this whole discussion should be expanded to include other security techniques realated to routing. Like I said, IMHO. Guy —Preceding unsigned comment added by Allgoodguy (talk • contribs)

The method you explained is not actually null routing, rather just a DNS hack. Routes can be added in Windows using the 'route' command line tool, but I am not sure what's the "proper" way to define a null route. Note that routing table entries do not persist through reboots. -- intgr [talk] 16:52, 4 May 2008 (UTC)

Wikipedia article talk pages are generally intended for comments about improving that article rather than general questions. That said, and since you have been waiting seven years for the answer, here's the command to null route 208.80.152.0 netmask 255.255.252.0 (the IP block for Wikipedia).

route -p ADD 208.80.152.0 MASK 255.255.252.0 0.0.0.0 IF 1

• -p makes the route persistent - it will remain in place after a reboot.
• You can use any IP address after the netmask value. I used 0.0.0.0 in this example but could have used 1.2.3.4. Oddly, if you use one of the 127.x.x.x addresses such as 127.0.0.0 the command is accepted but the route is not added to the routing table. Logically, this should work to add null-route but doesn't: route -p ADD 208.80.152.0 MASK 255.255.252.0 127.0.0 IF 1
• IF 1 is the key to adding the null-route. It's the loopback interface.

If you cut yourself off from Wikipedia the command to undo the damage is route DELETE 208.80.152.0

--Marc Kupper|talk 01:29, 30 July 2013 (UTC)

Stateless nature of routers - not true

That statement is probably true for IPv4 routers, but IPv6 introduced a "flow label" which can speedup processing in routers by introducing a "statefulness" of the routing decision for six seconds. — Preceding unsigned comment added by 80.187.110.232 (talk) 08:41, 22 November 2016 (UTC)

Other uses for null routes

Article is missing information on uses of null routes other than for black-holing unwanted traffic. For example, if I have been assigned public IP addresses 203.0.113.1-203.0.113.254 and use them as a NAT pool on the WAN side of my router, I need to advertise 203.0.113.0/24 as a null route... but why? 2600:1003:B013:2700:0:6C:2615:8001 (talk) 14:02, 5 April 2017 (UTC)