August 2014 - Bird-users

New in BIRD
by Ilias Pallikarakis 23 Aug '16

23 Aug '16

Hi, I recently started trying to learn BIRD. I should also mention I have no previous experience with any other Routing daemon either. I want to configure a bgp monitor for both ipv4 and ipv6. I am running BIRD in a Ubuntu 13.10 VM. I managed to install both bird and bird6 but I have some problems with the configurations. In ipv4 : I created a very simple configuration which I attach. The conf is compiled but in birdc the bgp session is considered idle. I tried to do a tcpdump and found that the router sends a TCP SYN on the VM's bgp port but the VM responds with a RST and never tries to set a BGP session itself. In ipv6 : No matter the configuration (my configuration or the sample coming with bird6 or examples found on the web) the configuration is not compiled giving the following error : BIRD ipv6 doesn't run (bird: /usr/local/etc/bird6.conf, line 1: Router ID must be configured manually on IPv6 routers) Could anyone give me some pointers on what I am doing wrong ? Thank you for your help, Ilias Pallikarakis

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IS-IS
by kveri new 01 Jun '15

01 Jun '15

Hello, I would like to implement IS-IS as a part of my master thesis. Are there any apparent problems which would prevent successful implementation, political and/or technical? Also I would like to hear opinions of the authors. Implementation timeframe is 2013 (if we live past 21th). Regards, Martin Čechvala Faculty of Informatics and Information Technologies Slovak Technical University

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RIP not doing "triggered update" following route deletion
by Tore Anderson 15 Oct '14

15 Oct '14

I've noticed that BIRD doesn't withdraw (i.e., advertising them with metric 16) RIP routes when they disappear from the routing table. This means that the neighbour router ends up waiting for the route to time out before ceasing to send traffic to the BIRD router, rather than doing so immediately. I'm running v1.4.0 with a bird.conf containing: log syslog { info, remote, warning, error, auth, fatal }; router id 192.0.2.1; protocol device {} protocol direct {} protocol rip { interface "*" { mode nolisten; ttl security on; }; import none; export all; } To reproduce the issue, look at "tcpdump -v port 520" while doing: 1) ip address add 192.0.2.2/32 dev lo -> a triggered update appears (advertising 192.0.2.2/32) 2) ip address delete 192.0.2.2/32 dev lo -> a triggered update doesn't appear (it should have) For what it's worth, step #2 does increase the RIP protocol's "Export withdraws" counter. This issue also applies to RIPng/bird6. AFAICT, not sending these triggered updates immediately is a standards violation. Quoting RFC 1812 F.2: «A router MUST send a triggered update when routes are deleted or their metrics are increased.» Also see RFC 2453 section 3.10.1. Tore

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Version 1.4.4
by Ondrej Filip 07 Oct '14

07 Oct '14

Dear Bird users, the new version is out: Version 1.4.4 o Extended OSPF multipath support. o Default router preference for RAdv. o Significant changes in socket layer. o Important bugfix in BGP. o Several minor bugfixes. Ondrej

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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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BFD implementation in 1.4.0
by Aleksey Berezin 02 Sep '14

02 Sep '14

Hi there! Firstly, sorry for my French ;) Recently I tried to test BFD implementation in 1.4.0 BIRD release. Case is "OSPF ECMP with less-second failover". On one side - Extreme Networks switches, other side - several boxes with Debian and BIRD, of course. So, I find out several annoying things. First thing: BIRD BFD implementation uses non-RFC5881 source UDP port for outgoing packets. Here some tcpdump: =-=-=--=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= 20:34:21.355747 <BIRD_BOX_MAC> > <EXTREME_SW_MAC>, ethertype 802.1Q (0x8100), length 70: vlan <vlan>, p 0, ethertype IPv4, (tos 0xc0, ttl 255, id 20806, offset 0, flags [none], proto UDP (17), length 52) <BIRD_BOX_IP>.39156 > <EXTREME_SW_IP>.3784: BFDv1, length: 24 Control, State Init, Flags: [none], Diagnostic: No Diagnostic (0x00) Detection Timer Multiplier: 5 (5000 ms Detection time), BFD Length: 24 My Discriminator: 0x8a82eb8a, Your Discriminator: 0x00000002 Desired min Tx Interval: 1000 ms Required min Rx Interval: 10 ms Required min Echo Interval: 0 ms =-=-=--=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= I saw many messages in switch logs: > <Warn:BFD.RxPktInv> Received BFD an invalid packet on VLAN <vlan> Error:Invalid UDP src port Number BFD session between BIRD and Extreme Networks switch can't be established. So, src port for outgoing BFD-packet from BIRD is 39156, when RFC5881 contains: =-=-=--=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= 4. Encapsulation BFD Control packets MUST be transmitted in UDP packets with destination port 3784, within an IPv4 or IPv6 packet. The source port MUST be in the range 49152 through 65535. =-=-=--=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Ok, fixing (only for test purposes): =-=-=--=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= root@debian-1:~# sysctl net.ipv4.ip_local_port_range net.ipv4.ip_local_port_range = 32768 61000 root@debian-1:~# sysctl -w net.ipv4.ip_local_port_range="49152 65535" net.ipv4.ip_local_port_range = 49152 65535 root@debian-1:~# sysctl net.ipv4.ip_local_port_range net.ipv4.ip_local_port_range = 49152 65535 =-=-=--=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= After this BFD session was estabilished. Of course, net.ipv4.ip_local_port_range tuning seems to be not usable in production environment, and need to be fixed in BIRD, I think. Just because some network hardware vendors interprets RFC's exactly as written ;) But now - second thing: 'protocol bfd' block in bird.conf useless. Here part of config: =-=-=--=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= protocol bfd FOR_OSPF { interface <BIRD_BOX_IP>/32 { interval 50 ms; min rx interval 50 ms; # presence of this string by the docs does not matter min tx interval 50 ms; # presence of this string by the docs does not matter multiplier 3; }; neighbor <EXTREME_SW_IP> dev "<BIRD_BOX_IP>" local <BIRD_BOX_IP>; # presence of this string by the docs does not matter }; protocol ospf OSPF1 { ... area 0.0.0.0 { interface <BIRD_BOX_IP>/32 { ... bfd; }; }; ... }; =-=-=--=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= And what I see with tcpdump: =-=-=--=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= 13:09:05.433336 <BIRD_BOX_MAC> > <EXTREME_SW_MAC>, ethertype 802.1Q (0x8100), length 70: vlan <vlan>, p 0, ethertype IPv4, (tos 0xc0, ttl 255, id 6662, offset 0, flags [none], proto UDP (17), length 52) <BIRD_BOX_IP>.62698 > <EXTREME_SW_IP>.3784: BFDv1, length: 24 Control, State Up, Flags: [none], Diagnostic: No Diagnostic (0x00) Detection Timer Multiplier: 5 (500 ms Detection time), BFD Length: 24 My Discriminator: 0x35e75227, Your Discriminator: 0x00000007 Desired min Tx Interval: 100 ms Required min Rx Interval: 10 ms Required min Echo Interval: 0 ms =-=-=--=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= There is no any configured intervals and multiplier. Just default values. I think this is not correct. Maybe I misconfigure BIRD? Please advise. Thanks for attention.

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export filter that checks for existance of another route?
by Paul J R 02 Sep '14

02 Sep '14

Hi All, First time post, i've been playing with bird for some time, but there is one thing i cant figure out how to do and that is use the existence of a specific route as part of a filter. for example, if the filter is processing a route to 4.3.2.0/24, check if a route to 1.2.3.4/32 (exact) exists, if so then accept, otherwise reject. Is this something that is possible? or do route filters only have the ability to check against the information thats sent to the filter itself? Thanks in advance, PJR.

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Limit on kernel table number
by Alexander Demenshin 02 Sep '14

02 Sep '14

Hi, It seems that there is a limit on maximum kernel table number (in kernel protocol), in particular I couldn't use number 1000 while this is perfectly acceptable by the Linux kernel. Is there any specific reason for this limitation? Thank you! -- With best regards, Alexander.

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show route all filter ...
by Mikhail A. Grishin 02 Sep '14

02 Sep '14

Hi, We use special command (see below) to view information regarding prefixes containing particular BGP communities. When such commands applied, we noticed in logs ---- Aug 27 11:50:17 ekt-rsm1 bird: Filter <NULL> did not return accept nor reject. Make up your mind Aug 27 11:50:17 ekt-rsm1 last message repeated 2690 times ---- Could you explain why? Is there any way to avoid such messages and stay at current logging level? Aug 27 11:50:17 ekt-rsm1 bird: CLI connect Aug 27 11:50:17 ekt-rsm1 bird: CLI: show route all filter {if (0,48642) ~ bgp_community then accept;} table master Aug 27 11:50:17 ekt-rsm1 bird: Filter <NULL> did not return accept nor reject. Make up your mind Aug 27 11:50:17 ekt-rsm1 last message repeated 2690 times Aug 27 11:50:17 ekt-rsm1 bird: CLI connection closed -- Best regards, Mikhail A. Grishin <m.grishin(a)msk-ix.ru>

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OSPF Route
by Jason Aeschilman 26 Aug '14

26 Aug '14

I am using bird 1.4.0. I configured OSPF and the routes that bird adds to Linux have a metric of 0. Then I added a static route with the same network and mask and it has a metric of 1. So now a route that OSPF has added has preference over a static route but this is not the behavior I see with quagga or Cisco. With them, the static route has preference. quagga adds routes with metrics (values 11+) relative to OSPF cost while Cisco does not add an OSPF route to the FIB if a matching static route already exists. My expectation, if bird is going to use metric 0, is that it should not add an OSPF route if a static route already exists with the same network and mask. Or if it must add an OSPF route, it should have a metric such that the static route takes precedence. Is it possible to change this behavior in the config? If so, how?

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