Can you not accomplish the same thing with the RP_Filter option in
IP/Settings? I'm just asking - I don't know.
http://wiki.mikrotik.com/wiki/Manual:IP/Settings
Rory McCann
MKAP Technology Solutions
Web: www.mkap.net
On 1/12/2015 11:46 AM, Dennis Burgess wrote:
Basically ,any IPs that SHOULD be sourced from your network. But yes,
the idea behind BCP38 is to block src address packets originating from
your network that SHOULD NOT. So yes, you should already have those
rules to not all traffic from your network if it’s coming from a IP
that should not come from your network, and yes that would include any
customer originated traffic.
An example, customer has 4 /19s and two /22s, plus has about 30 BGP
peers for customer traffic.
The 5 prefixes would be allowed out, plus any prefixes learned by the
bgp peers. If there were two upstream on the same router, both would
have a line, if the SRC address is ! (not) customer prefixes,
including the 5 prefixes they use, then it would be dropped on egress
of the upstream ports. An example of this is
add action=drop chain=forward out-interface=ether17-internet
src-address-list=!Inside-IPs
The inside_ips list include the local prefixes and the customer prefixes.
Dennis Burgess, CTO, Link Technologies, Inc.
[email protected] <mailto:[email protected]> – 314-735-0270 –
www.linktechs.net <http://www.linktechs.net>
*From:*Af [mailto:[email protected]] *On Behalf Of *Ken Hohhof
*Sent:* Monday, January 12, 2015 10:55 AM
*To:* [email protected]
*Subject:* Re: [AFMUG] BCP38
Yeah, I’m missing what the big deal is here. If you’re talking about
your border router to your upstream, why would you allow outbound
traffic with source IPs outside your IP blocks? Allow your IPs, block
the rest.
If you’re talking about other routers within your network and are
wanting to stop the traffic at the source, it could get more
complicated since I assume we all use some private IP space within our
networks for various purposes mostly management addresses on network
equipment.
Dennis mentions customer IPs, if you route customer blocks those would
also be allowed, based on an LOA.
*From:*Dennis Burgess <mailto:[email protected]>
*Sent:*Monday, January 12, 2015 10:43 AM
*To:*[email protected] <mailto:[email protected]>
*Subject:*Re: [AFMUG] BCP38
Very simple. In MT we do an address list of all valid subnets behind
the core routers, this would include any prefixes that you own or use,
plus any BGP prefixes learned from your customers. Then a simple, out
interface (internet) drop if its not SRCed from that list. Not
exactly IP tables, but there ya go..
Dennis Burgess, CTO, Link Technologies, Inc.
[email protected] <mailto:[email protected]> – 314-735-0270 –
www.linktechs.net <http://www.linktechs.net>
*From:*Af [mailto:[email protected]] *On Behalf Of *Sean Heskett
*Sent:* Monday, January 12, 2015 10:25 AM
*To:* [email protected] <mailto:[email protected]>
*Subject:* Re: [AFMUG] BCP38
Hey Mike,
Would you be willing to post an iptables statement that would drop
this traffic?
Thanks,
Sean
On Monday, January 12, 2015, Mike Hammett <[email protected]
<mailto:[email protected]>> wrote:
http://www.bcp38.info/index.php/Main_Page
Make sure you implement this in your networks. Drop all outbound
traffic to your upstream that is not from valid public IP space.
-----
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com
