North American Network Operators Group|
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Re: private ip addresses from ISP
In reality, from what I see, most large ISP doesn't care about RFC1918.
I've been dealing with this issue for a while.
Not all of them, because I didn't deal with all of them.
But some of them has strange policy for ACL, because it has large impact on router platform CPU utilization.
Strictly some ISP doesn't allow to put ACL for more than 24 hours including RFC1918 ip address space originated traffic.
So I'm doing it from our core router to block those traffic, and fun to watch the counters increasing so rapidly. ^.^
For an example,
[email protected]> show firewall filter XXX-in
Name Bytes Packets
XXX-in-default 430738360735883 743436641099
XXX-in-rfc1918-10 12742937908 41900221
XXX-in-loopback 785367140 2678266
XXX-in-dhcp-default 36982506 413978
XXX-in-rfc1918-172-16 1240646548 13026411
XXX-in-test-net 44318 621
XXX-in-rfc1918-192-168 1806857741 17309861
XXX-in-reserved-e-class 0 0
ospf-deny 14135 35
h323 8785570 186042
XXX-in-microsoft 305199975828 5751955784
ms-exclude 424428929 696688
on-fire 173190029170 5970455314
I'm wondering whether this is really about router platform issue, and they want their customer including smaller ISPs to bill more because of these junk traffic.
Andrew Kirch wrote:
-----Original Message----- From: [email protected] [mailto:[email protected]] On BehalfOfDavid Schwartz Sent: Wednesday, May 17, 2006 1:37 PM To: [email protected] Subject: RE: private ip addresses from ISPOur router is running BGP and connecting to our upstream provider with /30 network. Our log reveals that there are private IP addresses reaching our router's interface that is facing our upstream ISP. How could this be possible? Should upstream ISP be blocking private IP address according to standard configuration? Could the packet be stripped and IP be converted somehow during the transition? It happens in many Tier-1 ISP though ! Thank you for your informationDo you mean: 1) You are seeing BGP routes for addresses inside private space? 2) You are seeing packets with destination IPs inside privatespacearriving at your interface from your ISP? 3) You are seeing packets with source IPs inside private space arriving at your interface from your ISP? If 1, feel free to filter them. You ISP probably uses them internally and is leaking them to you. Feel free to complain if you want. If 2, make sure you aren't advertising routes into RFC1918 spacetoyour ISP. If not, you should definitely ask them what's up. If 3, that's normal. These are packets your ISP received thatareaddressed to you and the ISP is leaving to you the decision of whether to accept them or not. Feel free to filter them out if you wish. (It won't breakanythingSorry to dig this up from last week but I have to strongly disagree withthat's not already broken.)