nanog mailing list archives
Re: algorithm used by (RIPE region) ISPs to generate automatic BGP prefix filters
From: Pavel Odintsov <pavel.odintsov () gmail com>
Date: Thu, 4 Feb 2016 15:13:48 +0300
Hello! You could check awesome project for this purposes: http://www.stableit.ru/2015/06/generate-bgp-filters-with-bgpq3.html It's authored by Russian carrier RETN.net. On Thu, Feb 4, 2016 at 2:58 PM, Henrik Thostrup Jensen <htj () nordu net> wrote:
Hi Martin On Thu, 4 Feb 2016, Martin T wrote:am I correct that ISPs (in RIPE region), who update their BGP prefix filters automatically, ask their IP transit customer or peering partner to provide their "route"/"route6" object(s) or "as-set" object in order to find all the prefixes which they should accept?This is a common practice to do. Both within and outside the RIPE region. For bigger networks, prefix lists become somewhat unwieldy, and one can then use as-path filters instead. Use a prefix limit with this. Typically you use a tool (bgpq3) to generate the prefix lists.If the IP transit customer or peering partner provides an "as-set", then ISP needs to ensure that this "as-set" belongs to this IP transit customer or peering partner because there is no automatic authentication for this, i.e. anybody can create an "as-set" object to database with random "members" attributes?I don't know the procedure for creating as-sets, maybe someone else can chip in.This is opposite to "route"/"route6" objects which follow a strict authentication scheme.I believe this differs depending on the irrd software/operator.In addition, in case of "as-set", an ISP needs to recursively find all the AS numbers from "members" attributes because "as-set" can include other "as-sets"?Some irrd servers, can expand this automatically (I think). But seriously, use a tool for this.Quite a lot of question, but I would simply like to be sure that I understand this correctly.There are basically two abstractions: 1. as-set. Can contain other as-sets or as numbers. 2. prefixes are registered to an as-number. Remember that there are multiple IRR servers, and they mirror each other. Use http://irrexplorer.nlnog.net/ to play around a bit :-). Best regards, Henrik Henrik Thostrup Jensen <htj at nordu.net> Software Developer, NORDUnet
-- Sincerely yours, Pavel Odintsov
Current thread:
- algorithm used by (RIPE region) ISPs to generate automatic BGP prefix filters Martin T (Feb 04)
- Re: algorithm used by (RIPE region) ISPs to generate automatic BGP prefix filters Henrik Thostrup Jensen (Feb 04)
- Re: algorithm used by (RIPE region) ISPs to generate automatic BGP prefix filters Pavel Odintsov (Feb 04)
- Re: algorithm used by (RIPE region) ISPs to generate automatic BGP prefix filters Jared Mauch (Feb 04)
- Re: algorithm used by (RIPE region) ISPs to generate automatic BGP prefix filters Randy Bush (Feb 04)
- Re: algorithm used by (RIPE region) ISPs to generate automatic BGP prefix filters Jared Mauch (Feb 04)
- Re: algorithm used by (RIPE region) ISPs to generate automatic BGP prefix filters Randy Bush (Feb 04)
- Re: algorithm used by (RIPE region) ISPs to generate automatic BGP prefix filters Jared Mauch (Feb 04)
- Re: algorithm used by (RIPE region) ISPs to generate automatic BGP prefix filters Henrik Thostrup Jensen (Feb 04)