1560d73d1fb602eda20ffd821d181033077b1570
howto/.md
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| 1 | +To quote from <https://frrouting.org/>: |
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| 2 | + |
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| 3 | +"FRRouting (FRR) is a free and open source Internet routing protocol suite for Linux and Unix platforms. It implements BGP, OSPF, RIP, IS-IS, PIM, LDP, BFD, Babel, PBR, OpenFabric and VRRP, with alpha support for EIGRP and NHRP." |
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| 4 | + |
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| 5 | +It features a similar configuration style to Cisco IOS. |
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| 6 | + |
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| 7 | +### Installation |
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| 8 | +Install the `frr` and `frr-pythontools` package on your favourite Linux/BSD distribution. For BGP RPKI support, also install `frr-rpki`. _Make sure you are using frr version 8.5 or greater for IPv6 link local peerings._ |
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| 9 | + |
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| 10 | +- More installation options: <https://docs.frrouting.org/en/latest/installation.html> |
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| 11 | +- Releases: <https://frrouting.org/release/> |
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| 12 | + |
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| 13 | +## Configuration |
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| 14 | + |
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| 15 | +Important cofiguration files: |
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| 16 | +- `/etc/frr/daemons`: daemons that will be started |
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| 17 | +- `/etc/frr/vtysh.conf`: configuration for the VTY shell |
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| 18 | +- `/etc/frr/frr.conf`: configuration for the daemons |
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| 19 | +- `/etc/frr/${DAEMON}.conf`: configuration for a single daemon (deprecated) |
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| 20 | + |
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| 21 | +It this guide, only BGP will be set up using the shared `/etc/frr/frr.conf`. |
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| 22 | + |
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| 23 | +### Daemons |
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| 24 | + |
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| 25 | +First, setup `/etc/frr/daemons`. As stated previously. this file specifies which daemons will be started. |
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| 26 | + |
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| 27 | +```diff |
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| 28 | +--- /etc/frr/daemons |
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| 29 | ++++ /etc/frr/daemons |
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| 30 | +@@ -14,7 +14,7 @@ |
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| 31 | + # |
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| 32 | + # The watchfrr, zebra and staticd daemons are always started. |
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| 33 | + # |
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| 34 | +-bgpd=no |
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| 35 | ++bgpd=yes |
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| 36 | + ospfd=no |
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| 37 | + ospf6d=no |
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| 38 | + ripd=no |
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| 39 | +``` |
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| 40 | + |
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| 41 | +### VTY shell |
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| 42 | + |
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| 43 | +To use the VTY shell, `/etc/frr/vtysh.conf` needs to be set up. _The `hostname` and `banner motd` also need to be entered there manually to be persistant._ |
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| 44 | + |
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| 45 | +``` |
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| 46 | +service integrated-vtysh-config |
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| 47 | +``` |
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| 48 | + |
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| 49 | +Unprivileged users need to be in the `frrvty` group to use `vtysh`. |
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| 50 | + |
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| 51 | +The VTY shell can be used to interact with running daemons and configure them. Changes made in the VTY shell can be written to `/etc/frr/frr.conf` using the `write` command. To enter configuration mode use the `configure` command. To get information about the available commands, press `?`. |
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| 52 | + |
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| 53 | +### Zebra |
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| 54 | + |
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| 55 | +Before configuring BGP, a few other things need to be set up. First, create a [prefix-list](https://docs.frrouting.org/en/latest/filter.html#ip-prefix-list) for the dn42 prefixes. That will be used to filter out non-dn42 routes to be announced to BGP. For that, open `/etc/frr/frr.conf` or `vtysh` in configuration mode and add: |
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| 56 | + |
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| 57 | +``` |
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| 58 | +ip prefix-list dn42 seq 1 deny 172.22.166.0/24 le 32 |
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| 59 | +ip prefix-list dn42 seq 1001 permit 172.20.0.0/24 ge 28 le 32 |
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| 60 | +ip prefix-list dn42 seq 1002 permit 172.21.0.0/24 ge 28 le 32 |
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| 61 | +ip prefix-list dn42 seq 1003 permit 172.22.0.0/24 ge 28 le 32 |
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| 62 | +ip prefix-list dn42 seq 1004 permit 172.23.0.0/24 ge 28 le 32 |
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| 63 | +ip prefix-list dn42 seq 1100 permit 172.20.0.0/14 ge 21 le 29 |
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| 64 | +ip prefix-list dn42 seq 2001 permit 10.100.0.0/14 le 32 |
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| 65 | +ip prefix-list dn42 seq 2002 permit 10.127.0.0/16 le 32 |
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| 66 | +ip prefix-list dn42 seq 2003 permit 10.0.0.0/8 ge 15 le 24 |
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| 67 | +ip prefix-list dn42 seq 3001 permit 172.31.0.0/16 le 32 |
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| 68 | +ip prefix-list dn42 seq 9999 deny 0.0.0.0/0 le 32 |
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| 69 | +! |
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| 70 | +ipv6 prefix-list dn42v6 seq 1001 permit fd00::/8 ge 44 le 64 |
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| 71 | +ipv6 prefix-list dn42v6 seq 9999 deny ::/0 le 128 |
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| 72 | +``` |
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| 73 | + |
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| 74 | +This prefix list can be created yourself by following the instructions for Quagga in the `data/filter.txt` and `data/filter6.txt` files from the registry. |
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| 75 | + |
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| 76 | +Next create a [route-map](https://docs.frrouting.org/en/latest/routemap.html), which will be used for doing the actual filtering later. |
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| 77 | + |
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| 78 | +``` |
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| 79 | +route-map dn42 permit 5 |
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| 80 | + match ip address prefix-list dn42 |
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| 81 | + set src <IPv4 address of the node> |
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| 82 | +exit |
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| 83 | +! |
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| 84 | +route-map dn42v6 permit 5 |
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| 85 | + match ipv6 address prefix-list dn42v6 |
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| 86 | + set src <IPv6 address of the node> |
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| 87 | +exit |
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| 88 | +``` |
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| 89 | + |
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| 90 | +### BGP |
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| 91 | + |
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| 92 | +With the configuration of the daemons file and Zebra done, BGP can now be configured. |
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| 93 | + |
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| 94 | +``` |
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| 95 | +router bgp <AS of the network> |
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| 96 | + neighbor <IPv4 peer address> remote-as <Peer AS> |
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| 97 | + neighbor <IPv6 peer address> remote-as <Peer AS> |
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| 98 | + ! In case an IPv6 link local address is used to peer |
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| 99 | + neighbor <IPv6 peer address> interface <Peer interface> |
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| 100 | + ! |
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| 101 | + address-family ipv4 unicast |
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| 102 | + neighbor <IPv4 peer address> activate |
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| 103 | + neighbor <IPv4 peer address> route-map dn42 in |
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| 104 | + neighbor <IPv4 peer address> route-map dn42 out |
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| 105 | + exit |
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| 106 | + ! |
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| 107 | + address-family ipv6 unicast |
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| 108 | + neighbor <IPv6 peer address> activate |
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| 109 | + neighbor <IPv6 peer address> route-map dn42v6 in |
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| 110 | + neighbor <IPv6 peer address> route-map dn42v6 out |
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| 111 | + exit |
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| 112 | +exit |
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| 113 | +``` |
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| 114 | + |
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| 115 | +With everything configured, the BGP session should come up. In the normal VTY shell mode the status of BGP peerings can be checked using the `show bgp summary` command. |
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| 116 | + |
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| 117 | +### Complete configuration example |
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| 118 | + |
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| 119 | +``` |
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| 120 | +router bgp <Your AS here> |
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| 121 | + neighbor <Peer IPv4> remote-as <Peer AS> |
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| 122 | + neighbor <Peer IPv6> remote-as <Peer AS> |
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| 123 | + ! In case an IPv6 link local address is used to peer |
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| 124 | + neighbor <Peer IPv6> interface <Peer interface> |
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| 125 | + ! |
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| 126 | + address-family ipv4 unicast |
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| 127 | + neighbor <IPv4 peer address> activate |
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| 128 | + neighbor <IPv4 peer address> route-map dn42 in |
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| 129 | + neighbor <IPv4 peer address> route-map dn42 out |
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| 130 | + exit |
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| 131 | + ! |
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| 132 | + address-family ipv6 unicast |
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| 133 | + neighbor <IPv6 peer address> activate |
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| 134 | + neighbor <IPv6 peer address> route-map dn42v6 in |
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| 135 | + neighbor <IPv6 peer address> route-map dn42v6 out |
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| 136 | + exit |
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| 137 | +exit |
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| 138 | +! |
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| 139 | +ip prefix-list dn42 seq 1 deny 172.22.166.0/24 le 32 |
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| 140 | +ip prefix-list dn42 seq 1001 permit 172.20.0.0/24 ge 28 le 32 |
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| 141 | +ip prefix-list dn42 seq 1002 permit 172.21.0.0/24 ge 28 le 32 |
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| 142 | +ip prefix-list dn42 seq 1003 permit 172.22.0.0/24 ge 28 le 32 |
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| 143 | +ip prefix-list dn42 seq 1004 permit 172.23.0.0/24 ge 28 le 32 |
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| 144 | +ip prefix-list dn42 seq 1100 permit 172.20.0.0/14 ge 21 le 29 |
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| 145 | +ip prefix-list dn42 seq 2001 permit 10.100.0.0/14 le 32 |
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| 146 | +ip prefix-list dn42 seq 2002 permit 10.127.0.0/16 le 32 |
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| 147 | +ip prefix-list dn42 seq 2003 permit 10.0.0.0/8 ge 15 le 24 |
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| 148 | +ip prefix-list dn42 seq 3001 permit 172.31.0.0/16 le 32 |
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| 149 | +ip prefix-list dn42 seq 9999 deny 0.0.0.0/0 le 32 |
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| 150 | +! |
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| 151 | +ipv6 prefix-list dn42v6 seq 1001 permit fd00::/8 ge 44 le 64 |
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| 152 | +ipv6 prefix-list dn42v6 seq 9999 deny ::/0 le 128 |
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| 153 | +! |
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| 154 | +route-map dn42 permit 5 |
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| 155 | + match ip address prefix-list dn42 |
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| 156 | + set src <IPv4 address of the node> |
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| 157 | +exit |
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| 158 | +! |
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| 159 | +route-map dn42v6 permit 5 |
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| 160 | + match ipv6 address prefix-list dn42v6 |
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| 161 | + set src <IPv6 address of the node> |
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| 162 | +exit |
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| 163 | +``` |
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| 164 | + |
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| 165 | +## Further reading |
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| 166 | + |
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| 167 | +### General things |
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| 168 | + |
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| 169 | +- FRR documentation: <https://docs.frrouting.org/en/latest> |
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| 170 | +- FRR source code: <https://github.com/frrouting/frr> |
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| 171 | + |
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| 172 | +### Configuration tipps |
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| 173 | + |
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| 174 | +- Use [peer groups](https://docs.frrouting.org/en/latest/bgp.html#peer-groups) (_Strongly reccomended to limit the work neede to add new peers or change general configuration for may peers._) |
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| 175 | +- `tab` and `?` are your best friends in the VTY shell |
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| 176 | +- Use `find REGEX` in the VTY shell to find certain commands |