September 2014 - Bird-users

question: importing routes from kernel filtered by function with prefix match
by Kai 22 Sep '14

22 Sep '14

Dear experienced bird experts! :) While trying to setup my first more complex bird config I cannot determine the error I made that impede my config from working. Excerpt from the config: table kern_wimz; function is_wimz_self_nets() { return (net ~ [10.56.0.0/16+, 10.37.0.0/16+]); } # import only self from kernel, export anything but wi&mz - remark: exporting done by other kernel protocoll instances protocol kernel kern_import { scan time 30; import where is_wimz_self_nets(); export none; table kern_wimz; kernel table 254; # main }; I also added a - seemingly neccessary: table bla; protocol device { scan time 30; table bla; }; (Complete config: https://github.com/freifunk-mwu/technik-meta/wiki/birdconfig ) In the main kernel routing table (#254) one can find - among others - the two prefixes 10.37.0.0/18 and 10.56.0.0/18 . I expected these two to be imported into kern_wimz. From there they are going to be transported to other tables by the pipe protocol. But kern_wimz remains empty. :( I consulted the documentation multiple times already, but I cannot pinpoint the mistake I made. Could anyone please provide me with a helpful hint? Best regards, Kai

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constant rejected in router id ...
by Kai 22 Sep '14

22 Sep '14

Good Morning! When trying to use a previously defined constant value in a "router id", bird answers with a syntax error. Is this the intended behaviour? It would be quite handy to be able to use constants in this place also (as we have a multi-ASN-setup using the router-id-override within template-bgp-blocks). Example: define my_router_id = 10.11.12.13; router id my_router_id; Best regards, Kai

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Re: static route multipath problem
by Ondrej Zajicek 19 Sep '14

19 Sep '14

On Thu, Sep 18, 2014 at 02:56:32PM +0800, 守得云开 wrote: > can i setup like this, 11, 12 and 13 is the ip of ppp0, ppp1 and ppp2: > ------------------------------ > route 0.0.0.0/0 multipath > via 10.10.10.11 weight 2 > via 10.10.10.12 weight 3 > via 10.10.10.12 weight 4; This should work > ------------------------------ > or link this: > ------------------------------ > route 0.0.0.0/0 multipath > via 10.10.10.1 dev ppp0 weight 2 > via 10.10.10.1 dev ppp1 weight 3 > via 10.10.10.1 dev ppp2 weight 4; We do not currently support 'dev' option here, but you could use this: route 0.0.0.0/0 multipath via 10.10.10.1%ppp0 weight 2 via 10.10.10.1%ppp1 weight 3 via 10.10.10.1%ppp2 weight 4; This is syntax for link-local IPv6 addresses like fe80::1234:5678%eth0, but works also for regular IPv4 addresses. -- Elen sila lumenn' omentielvo Ondrej 'Santiago' Zajicek (email: santiago(a)crfreenet.org) OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) "To err is human -- to blame it on a computer is even more so."

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Shutting down BGP neighbor causes high CPU and many session flaps.
by Javor Kliachev 19 Sep '14

19 Sep '14

Hello, We use bird 1.4.2 as route server with multiple RIBs with ~100 BGP active sessions. Over one of these sessions, we're receiving ~ 360k prefixes and re-announcing them to all other sessions. By my calculations the total amount of all prefixes in all RIBs is about ~ 3600000 and till now everything was OK. *But today we have experienced the following issue: * When we stopped the session that we received ~360k, BIRD daemon went to 100% usage and held this behavior for period of~5-6 min. This event caused а lot of ( but not all ) sessions to start flapping. Here is the output taken from our log during the event: Sep 18 10:40:51 rs2 bird: R0_69: Received: Hold timer expired Sep 18 10:40:51 rs2 bird: R0_69: BGP session closed Sep 18 10:40:52 rs2 bird: R0_69: Down Sep 18 10:41:11 rs2 bird: R0_69: Startup delayed by 60 seconds Sep 18 10:41:45 rs2 bird: R0_69: Incoming connection from 10.0.0.69 (port 13073) rejected Sep 18 10:41:59 rs2 bird: R0_69: Started Sep 18 10:42:36 rs2 bird: R0_69: Incoming connection from 10.0.0.69 (port 24222) accepted Sep 18 10:42:36 rs2 bird: R0_69: BGP session established The above lines was repeated for all other affected sessions. After the CPU peak of 5 min, all affected sessions became UP again. Our CPU arch is 2 x Intel(R) Xeon(R) CPU E5310 1.6Ghz with 4 cores. I know BIRD that still may use only 1 CPU core but is there any plans to use more? We will highly appreciate for any suggestions or share some experience how to prevent in future such event. Thanks in advance! Best~ -- --- Find out about our new Cloud service - Cloudware.bg <http://cloudware.bg/?utm_source=email&utm_medium=signature&utm_content=link…> Access anywhere. Manage it yourself. Pay as you go. ------------------------------------------------------------------------ *Javor Kliachev* IP Engineer Neterra Ltd. Telephone: +359 2 975 16 16 Fax: +359 2 975 34 36 www.neterra.net <http://www.neterra.net>

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announcing BGP prefixes from the same AS at different sites?
by Thomas Johnson 10 Sep '14

10 Sep '14

I am trying to sort out a chicken-and-egg problem is probably more of a network design question than bird-specific. I am using bird to announce prefixes from two geographically-separate locations (A and B). I am announcing different prefixes at each, but with the same AS. The problem I am having is how to get these locations to add each other's routes. At location A, I have a pair of bird routers (X and Y), each connected to a different provider. Both routers announce the prefixes for this site over eBGP. These routers have an iBGP session between them. At location B, there is a single router (Z), connected to one ISP. It announces its own prefixes upstream. Since both sites announce with the same AS, they don't import the other's prefixes. An iBGP full-mesh seems to be the _correct_ solution, but I am having trouble getting this implemented correctly. If I configure the inter-site iBGP sessions to connect between the addresses on the WAN interfaces, I get partial success. At site A, router X correctly adds routes for site B. Router Y establishes a connection to router Z (site B), but adds the B prefixes as unreachable. The difference is that the Y->Z BGP connection (A->B direction) is routed via router X (shorter AS path via X ISP). My configuration files for this setup are below. If I attempt to establish the inter-site iBGP between the loopbacks on the routers, I have no success, since the loopback addresses fall with the subnets I announce at each site. Is there some bit of configuration I am missing? Am I going about this the wrong way? Any thoughts are appreciated. # # router Y # site A # protocol bgp bgp_he { local as 12345; neighbor 1.1.2.69 as 6939; # Export exactly what prefixes we want advertised. No surprises. export filter { if proto = "static_bgp" then accept; if proto = "portable_bgp" then accept; reject; }; # Import filtered routes from upstream. import filter bgp_in_he; } protocol bgp ibgp_border { local 6.9.5.212 as 12345; neighbor 6.9.5.213 as 12345; multihop 2; import filter { accept; }; export filter { if source != RTS_BGP then { reject; } if proto = "ibgp_border" then { reject; } accept; }; } protocol bgp ibgp_1b { local 1.1.2.70 as 12345; neighbor 7.4.2.132 as 12345; multihop 10; import filter { accept; }; export filter { if proto = "static_bgp" then accept; if proto = "portable_bgp" then accept; reject; }; } protocol ospf { # *snip* } # # router X # site A # protocol bgp bgp_cogent { local as 12345; neighbor 3.8.1.105 as 174; # Export exactly what prefixes we want advertised. No surprises. export filter { if proto = "static_bgp" then accept; if proto = "portable_bgp" && net.len <= 24 then accept; reject; }; # Import filtered routes from upstream. import filter bgp_in_cogent; } protocol bgp ibgp_border { local 6.9.5.213 as 12345; neighbor 6.9.5.212 as 12345; multihop 2; # Send all routes learnt via BGP import filter { accept; }; export filter { if source != RTS_BGP then { reject; } if proto = "ibgp_border" then { reject; } accept; }; } protocol bgp ibgp_1b { local 3.8.1.106 as 12345; neighbor 7.4.2.132 as 12345; multihop 10; import filter { accept; }; export filter { if proto = "static_bgp" then accept; if proto = "portable_bgp" && net.len <= 24 then accept; reject; }; } protocol ospf { # *snip* } # # router Z # site B # template bgp ibgp_A { debug all; local 7.4.2.132 as 12345; multihop 10; import filter { accept; }; export filter { if proto = "static_bgp" then accept; if proto = "standby_bgp" then accept; if proto = "portable_bgp" then accept; reject; }; } protocol bgp ibgp_Y from ibgp_A { neighbor 1.1.2.70 as 12345; }; protocol bgp ibgp_X from ibgp_A { neighbor 3.8.1.106 as 12345; }; template bgp B { # Set our local AS. local as 12345; # Export exactly what prefixes we want advertised. No surprises. export filter { if proto = "static_bgp" then accept; if proto = "standby_bgp" then accept; if proto = "portable_bgp" && net.len <= 24 then accept; reject; }; # Import filtered routes from upstream. import filter bgp_in_B; } protocol bgp bgp_B from B { neighbor 7.4.2.130 as 1212; };

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bgp router with multi asn's - neighbor config ?
by Kai 08 Sep '14

08 Sep '14

G'day! For the configuration we want to set up, I couldn't find any details in the docs, the wiki or the list archive. So please allow me to ask my questions here (questions see below). desired setup: We want to establish a router ('A') announcing two different ASNs (as1,as2) to it's neighbours. In fact we want to setup three routers A, B and C, all of them corporately announcing as1 and as2. I'd guess the config on router A should include some lines like these: protocol bgp { local as <as1>; neighbor X as as9; (...) } protocol bgp { local as <as2>; neighbor X as as9; (...) } X being one of the neighbours and announcing as9. Question 1: Is this basically the correct approach? Question 2: What would be the correct config on router X (A's neighbour) in this setup? Would it look like: protocol bgp { local as <as9>; neighbor A as as1; (...) } protocol bgp { local as <as9>; neighbor A as as2; (...) } Question 3: Does anyone have a pointer to a text/tutorial/whatever that explains in detail what config is needed for this kind of setup? Best regards, Kai -- "Das ist Demokratie, wenn man sich aussuchen darf, wer einen verarscht." (Hagen Rether) D-65203 Wiesi fast: kai_pf (aT] web(dot)de ++ PGP Key fingerprint B567 C43E 99D1 7709 7D64 3BF8 2DE8 1092 0EEF D58E ++ -----BEGIN GEEK CODE BLOCK----- VERSION: 3.12 GCS/IT/CM d- s:- a+>-----(?) C++$ UL++(++++$) P+++ L++ E-(+) W--(+) N !w---($) !O !M V? PS+ PE-() Y+ PGP(+) t R*@ tv--@ b+>++ DI++ G e+++(*) h? y? ------END GEEK CODE BLOCK------

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Bird keep routes from older bird process
by Antoine Habran 05 Sep '14

05 Sep '14

Hello, Sorry for my english, I hope you will understand me. I'm using "Bird" for his OSPF implementation and I have a technical question. I need to keep the routes learned from OSPF after any "Bird" stop or crashes. This can be done with the "persist" option into the kernel configuration block in the bird.conf file. But when I start "Bird" after a stop or a crash of the service, all routes was forgotten. It is possible to tell "Bird" to not erase kernel routes from older "Bird" process? Thanks in advance -- Antoine Habran https://doc.habran.eu

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Re: bgp router with multi asn's - neighbor config ?
by Leo Vandewoestijne 04 Sep '14

04 Sep '14

On Thu, 04 Sep 2014, Ondrej Zajicek wrote: > > listen bgp address 10.0.1.102 port 179; > > listen bgp address 10.0.2.102 port 179; > > I don't think you should have two 'listen bgp' options. AFAIK there is > only one listening BGP socket in BIRD, but it is OK to have it listen on > 0.0.0.0 (default value). Incoming sessions are dispatched based on their > source addresses. > Oh yes, that's true. In fact in FreeBSD defining two addresses now breaks it; I'm not sure if that's because I started to use version 10, or if something changed in Bird. And so I stopped doing that around January 2014. Before that, in 9 with a current version of Bird, it worked fine. -- Leo

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Multiple routing tables with multiple gateways
by Fernando Frediani 04 Sep '14

04 Sep '14

Hello there, I'm currently writing a project document which consists in a server to be hosted in a Internet Exchange Point, (similar to a route server but with another propose) and one of the things it must do is: When it receives a request coming from an IP range from ISP A it must go out to the internet using the ISP A gateway, when the request comes from ISP B IP range it goes out via that ISP router and so on. Any request originating on the server itself goes out via the Internet Exchange connectivity. I know this can be done using IProute2 and creating multiple routing tables, but I would rather automate it using BIRD, so the ISPs would establish a BGP session to the server, announce their IP range, but in a different way they do with a Route server as they would need also to announce default route, and BIRD would take care to inform the kernel for when the request comes from those IPs it needs to use the specific ISP gateway depending on the IP range. Would anyone be able to point me to the right direction in terms of BIRD BGP config in order to achieve that, specially with regards the main differences to a Route Server. Thanks Best regards, Fernando

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Does radv protocol (re)scan interfaces on IPv6?
by Alex Bligh 04 Sep '14

04 Sep '14

I am trying to isolate an issue with the radv protocol running on IPv6 I have possibly the world's simplest radv configuration: protocol radv evrradv { interface "-evrr-000000", "evrr-*" { max ra interval 4; }; } The idea here is that the router provides radv information on all interfaces with names starting evrr- except evrr-000000. What I am seeing is that if I add another interface, radv does not appear to work. A reload produces: # birdc6 reload evrradv BIRD 1.3.4 ready. evrradv: reload failed This doesn't help A restart produces: # birdc6 restart evrradv BIRD 1.3.4 ready. evrradv: restarted This fixes things, and radv appears to work. I am quite sure this used to work with the same software a little while ago, but it may be that I'm going mad. Should radv pick up creation and deletion of new interfaces? Might this be something related to the ordering of applying the IP address and taking the interface up or something? How is this meant to work? This is an old version of bird (1.3.4), but initial tests indicate the same is happening on a relatively recent version (I'll attempt to reproduce this further). I don't really want to restart bird6's radv protocol every time I add an interface as this is quite frequent. -- Alex Bligh

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