about ibgp config and ping Time exceeded: Hop limit

Question

I am configuring iBGP

Now there are two machines RS1 and RS2

They use Ubuntu 18 and bird 1.6

RS1 connected to as6939

RS2 connected to as20473

2000:1::/48 Announced on RS1

2000:2:: 48 Announced on RS2

RS1 and RS2 are connected through zerotier, and then iBGP is established

Their profile looks like this

RS1

router id 1.1.1.1;

function is_my_net()
{
        return net ~ [
                2000::/44+,
        ];
}

filter normal_out
{
        if proto = "Announce" then accept;
        if is_my_net() then accept;
        if proto = "NA" then reject;
        reject;
}

protocol static Announce
{
        route 2000:1::/48 reject; #tunnel
}


protocol static NA
{

}


protocol kernel
{
        scan time 60;
        import none;
        #export all;
        metric 2000;
}

protocol device
{
        scan time 60;
}

protocol direct {
        interface "*";
        import all;
}

template bgp ibgp {
        local fd15:9924:d630:e01c:2333:93f4:229e:9998 as 123456;
        import all;
        export all;
        graceful restart on;
}


protocol bgp ibgp_rs2 from ibgp {
        neighbor fd15:9924:d630:e01c:2333:9391:ba13:598b as 123456;
}


protocol bgp he
{
        local 2001:2333:2333:a4::2 as 123456;
        neighbor 2001:2333:2333:a4::1 as 6939;
        import all;
        export filter normal_out;
        graceful restart on;
}

protocol ospf myospf {
        import all;
        export where source ~ [ RTS_DEVICE, RTS_STATIC, RTS_OSPF ] && proto != "static_bgp" && proto != "static_bgp_vultr";
        area 0 {
                interface "bgp" {
                        cost 450;
                };
        };
}

RS2

router id 1.1.1.2;

function is_my_net()
{
        return net ~ [
                2000::/44+
        ];
}

filter normal_out
{
        if proto = "Announce" then accept;
        if is_my_net() then accept;
        if proto = "NA" then reject;
        reject;
}

protocol static Announce
{
        route 2000:2::/48 reject; #tunnel
}

protocol static NA
{

}

protocol static static_vultr {
        route 2001:19f0:ffff::1/128 via fe80::fc00:2333:fe88:2333%ens3;
}

protocol kernel
{
        scan time 60;
        import none;
        #export all;
        metric 2000;
}

protocol device
{
        scan time 60;
}

protocol direct {
        interface "*";
        import all;
}


protocol bgp vultr
{
        local 2001:19f0:4400:5132:5400:2333:fe88:2333 as 123456;
        neighbor 2001:19f0:ffff::1 as 64515;
        import all;
        export filter normal_out;
        graceful restart on;
        multihop 2;
        password "hidepasswd";
}

template bgp ibgp {
        local fd15:9924:d630:e01c:2333:9391:ba13:598b as 123456;
        import all;
        export all;
        graceful restart on;
}

protocol bgp ibgp_rs1 from ibgp {
        neighbor fd15:9924:d630:e01c:2333:93f4:229e:9998 as 123456;
}


protocol ospf myospf {
        import all;
        export where source ~ [ RTS_DEVICE, RTS_STATIC, RTS_OSPF ] && proto != "static_bgp" && proto != "static_bgp_vultr";
        area 0 {
                interface "bgp" {
                        cost 450;
                };
        };
}

in RS1 run birdc6 show route 2000:2::/48

root@rs1:~# birdc6 show route 2000:2::/48
BIRD 1.6.3 ready.
2000:2::/48 via fd15:9924:d630:e01c:2333:9391:ba13:598b on ztyou4jsxl [ibgp_rs2 14:10:51] * (100/0) [i]

in RS2 run birdc6 show route 2000:1::/48

root@rs2:~# birdc6 show route 2000:1::/48
BIRD 1.6.6 ready.
2000:1::/48  via fd15:9924:d630:e01c:2333:93f4:229e:9998 on ztyou4jsxl [ibgp_rs1 06:10:45] * (100/0) [i]

but i run traceroute6 2000:2:: on rs1

root@rs1:~# traceroute6 2000:2::
traceroute to 2000:2:: (2000:2::) from 2001:2333:2333:a4::2, 30 hops max, 24 byte packets
 1  tunnel562333.tunnel.tserv19.hkg1.ipv6.he.net (2001:2333:2333:a4::1)  2.144 ms  2.095 ms  1.969 ms
 2  tunnel562333-pt.tunnel.tserv19.hkg1.ipv6.he.net (2001:2333:2333:a4::2)  1.87 ms  21.406 ms  10.724 ms
 3  tunnel562333.tunnel.tserv19.hkg1.ipv6.he.net (2001:2333:2333:a4::1)  7.368 ms  3.664 ms  3.776 ms
 4  tunnel562333-pt.tunnel.tserv19.hkg1.ipv6.he.net (2001:2333:2333:a4::2)  3.396 ms  3.457 ms  3.546 ms
 5  tunnel562333.tunnel.tserv19.hkg1.ipv6.he.net (2001:2333:2333:a4::1)  5.58 ms  5.604 ms  5.788 ms
 6  tunnel562333-pt.tunnel.tserv19.hkg1.ipv6.he.net (2001:2333:2333:a4::2)  5.089 ms  5.405 ms  5.056 ms
 7  tunnel562333.tunnel.tserv19.hkg1.ipv6.he.net (2001:2333:2333:a4::1)  7.197 ms  7.266 ms  6.965 ms
 8  tunnel562333-pt.tunnel.tserv19.hkg1.ipv6.he.net (2001:2333:2333:a4::2)  6.64 ms  7.773 ms  7.013 ms

run traceroute6 2000:1:: on rs2

root@rs2:~# traceroute6 2000:1::
traceroute to 2000:1:: (2000:1::) from 2001:19f0:4400:5132:5400:2333:fe88:2333, 30 hops max, 24 byte packets
 1  * * *
 2  2001:19f0:4400:5132:5400:2333:fe88:2333 (2001:19f0:4400:5132:5400:2333:fe88:2333)  0.551 ms  0.164 ms  0.107 ms
 3  * * *
 4  2001:19f0:4400:5132:5400:2333:fe88:2333 (2001:19f0:4400:5132:5400:2333:fe88:2333)  0.445 ms  0.226 ms  0.138 ms
 5  * * *
 6  2001:19f0:4400:5132:5400:2333:fe88:2333 (2001:19f0:4400:5132:5400:2333:fe88:2333)  0.353 ms  0.251 ms  0.365 ms
 7  * * *
 8  2001:19f0:4400:5132:5400:2333:fe88:2333 (2001:19f0:4400:5132:5400:2333:fe88:2333)  0.346 ms  0.319 ms  0.216 ms

Just like traceroute6

IBGP does not work and destroys BGP routing

How can I solve this problem?

You showed what Bird thought the routes should be, but not what was installed in the Kernel routeing table (FIB). But in any case, would you be better off asking this question in the [Network Engineering](https://networkengineering.stackexchange.com/) forum ? — Chris Hall, Mar 13 '20 at 10:09

score 0 · Answer 1 · answered Mar 21 '20 at 02:05

0

This problem has been solved The problem is that the route is not export to the kernel

protocol kernel
{
        scan time 60;
        import none;
        export all;
        metric 2000;
}

In addition, I use OSPF to route IGP

answered Mar 21 '20 at 02:05

kagurazaka shira

33
1
6

about ibgp config and ping Time exceeded: Hop limit

1 Answers1