DOKK / manpages / debian 11 / bgpq4 / bgpq4.8.en
BGPQ4(8) System Manager's Manual BGPQ4(8)

bgpq4 — bgp filtering automation tool

bgpq4 [-h host[:port]] [-S sources] [-EPz] [-f asn | -F fmt | -G asn -t] [-46ABbDdJjNnsXU] [-a asn] [-r len] [-R len] [-m max] [-W len] OBJECTS [...] [EXCEPT OBJECTS]

The bgpq4 utility used to generate configurations (prefix-lists, extended access-lists, policy-statement terms and as-path lists) based on RADB data.

The options are as follows:

generate IPv4 prefix/access-lists (default).
generate IPv6 prefix/access-lists (IPv4 by default).
try to aggregate prefix-lists as much as possible (not all output formats supported).
asn
specify what asn shall be denied in case of empty prefix-list (OpenBGPD)
generate output in OpenBGPD format (default: Cisco)
generate output in BIRD format (default: Cisco).
enable some debugging output.
generate extended access-list (Cisco), policy-statement term using route-filters (Juniper), [ip|ipv6]-prefix-list (Nokia) or prefix-sets (OpenBGPd).
number
generate input as-path access-list.
fmt
generate output in user-defined format.
number
generate output as-path access-list.
host[:port]
host running IRRD database (default: rr.ntt.net).
generate config for Juniper (default: Cisco).
generate output in JSON format (default: Cisco).
generate config for Mikrotik (default: Cisco).
name
name of generated entry.
limit
limit recursion depth when expanding as-sets.
len
maximum prefix-length of accepted prefixes (default: 32 for IPv4 and 128 for IPv6).
match
extra match conditions for Juniper route-filters.
generate config for Nokia SR OS MD-CLI (Cisco IOS by default)
generate config for Nokia SR OS classic CLI (Cisco IOS by default).
accept routes registered for private ASNs (default: disabled)
generate prefix-list (default, backward compatibility).
len
allow more specific routes starting with specified masklen too.
len
allow more specific routes up to specified masklen too.
generate sequence numbers in IOS-style prefix-lists.
sources
use specified sources only (recommended: RADB,RIPE,APNIC).
generate as-sets for OpenBGPD (OpenBSD 6.4+), BIRD and JSON formats.
disable pipelining (not recommended).
len
generate as-path strings of no more than len items (use 0 for inifinity).
generate config for Huawei devices (Cisco IOS by default)
generate config for Cisco IOS XR devices (plain IOS by default).
generate route-filter-lists (JunOS 16.2+).
OBJECTS
means networks (in prefix format), autonomous systems, as-sets and route-sets.
EXCEPT OBJECTS
those objects will be excluded from expansion.

Generating named juniper prefix-filter for AS20597:

$ bgpq4 -Jl eltel AS20597
policy-options {
replace:
 prefix-list eltel {
    81.9.0.0/20;
    81.9.32.0/20;
    81.9.96.0/20;
    81.222.128.0/20;
    81.222.192.0/18;
    85.249.8.0/21;
    85.249.224.0/19;
    89.112.0.0/19;
    89.112.4.0/22;
    89.112.32.0/19;
    89.112.64.0/19;
    217.170.64.0/20;
    217.170.80.0/20;
 }
}

For Cisco we can use aggregation (-A) flag to make this prefix-filter more compact:

$ bgpq4 -Al eltel AS20597
no ip prefix-list eltel
ip prefix-list eltel permit 81.9.0.0/20
ip prefix-list eltel permit 81.9.32.0/20
ip prefix-list eltel permit 81.9.96.0/20
ip prefix-list eltel permit 81.222.128.0/20
ip prefix-list eltel permit 81.222.192.0/18
ip prefix-list eltel permit 85.249.8.0/21
ip prefix-list eltel permit 85.249.224.0/19
ip prefix-list eltel permit 89.112.0.0/18 ge 19 le 19
ip prefix-list eltel permit 89.112.4.0/22
ip prefix-list eltel permit 89.112.64.0/19
ip prefix-list eltel permit 217.170.64.0/19 ge 20 le 20

- you see, prefixes 89.112.0.0/19 and 89.112.32.0/19 now aggregated into single entry 89.112.0.0/18 ge 19 le 19.

Well, for Juniper we can generate even more interesting policy-options, using -M <extra match conditions>, -R <len> and hierarchical names:

$ bgpq4 -AJEl eltel/specifics -r 29 -R 32 -M "community blackhole" AS20597
policy-options {
 policy-statement eltel {
  term specifics {
replace:
   from {
    community blackhole;
    route-filter 81.9.0.0/20 prefix-length-range /29-/32;
    route-filter 81.9.32.0/20 prefix-length-range /29-/32;
    route-filter 81.9.96.0/20 prefix-length-range /29-/32;
    route-filter 81.222.128.0/20 prefix-length-range /29-/32;
    route-filter 81.222.192.0/18 prefix-length-range /29-/32;
    route-filter 85.249.8.0/21 prefix-length-range /29-/32;
    route-filter 85.249.224.0/19 prefix-length-range /29-/32;
    route-filter 89.112.0.0/17 prefix-length-range /29-/32;
    route-filter 217.170.64.0/19 prefix-length-range /29-/32;
   }
  }
 }
}
generated policy-option term now allows all specifics with prefix-length between /29 and /32 for eltel networks if they match with special community blackhole (defined elsewhere in configuration).

Of course, this version supports IPv6 (-6):

$ bgpq4 -6l as-retn-6 AS-RETN6
no ipv6 prefix-list as-retn-6
ipv6 prefix-list as-retn-6 permit 2001:7fb:fe00::/48
ipv6 prefix-list as-retn-6 permit 2001:7fb:fe01::/48
[....]
and assumes your device supports 32-bit ASNs 
$ bgpq4 -Jf 112 AS-SPACENET
policy-options {
replace:
 as-path-group NN {
  as-path a0 "^112(112)*$";
  as-path a1 "^112(.)*(1898|5539|8495|8763|8878|12136|12931|15909)$";
  as-path a2 "^112(.)*(21358|23456|23600|24151|25152|31529|34127|34906)$";
  as-path a3 "^112(.)*(35052|41720|43628|44450|196611)$";
 }
}

see `AS196611` in the end of the list ? That's a 32-bit ASN.

If you want to generate configuration not for routers, but for some other programs/systems, you may use user-defined formatting, like in example below:

$ bgpq4 -F "ipfw add pass all from %n/%l to any\n" as3254
ipfw add pass all from 62.244.0.0/18 to any
ipfw add pass all from 91.219.29.0/24 to any
ipfw add pass all from 91.219.30.0/24 to any
ipfw add pass all from 193.193.192.0/19 to any

Recognized format characters: %n - network, %l - mask length, %a - aggregate low mask length, %A - aggregate high mask length, %N - object name, %m - object mask and %i - inversed mask. Recognized escape characters: \n - new line, \t - tabulation. Please note that no new lines inserted automatically after each sentence, you have to add them into format string manually, elsewhere output will be in one line (sometimes it makes sense):

$ bgpq4 -6F "%n/%l; " as-eltel
2001:1b00::/32; 2620:4f:8000::/48; 2a04:bac0::/29; 2a05:3a80::/48;

When everything is OK, bgpq4 generates access-list to standard output and exits with status == 0. In case of errors they are printed to stderr and program exits with non-zero status.

BGPQ4 on Github.

Job Snijders ⟨job@ntt.net⟩

December 1, 2019 Debian