Document the `protocol PROTO` keyword, which tags a neighbour entry
with its origin (e.g. static, boot, dhcp, or a routing daemon's own
protocol id) on `ip neigh add/change/replace/delete`, and filters
entries by that origin on `ip neigh show/flush`, including the
special `all` value. Supported since 6b83edc0 ("neighbor: Add
support for protocol attribute").

Signed-off-by: Prijesh Patel <prijeshpatel.dev@gmail.com>
Assisted-by: Claude:claude-sonnet-5
---
 man/man8/ip-neighbour.8 | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/man/man8/ip-neighbour.8 b/man/man8/ip-neighbour.8
index 1f890c0d..4784faff 100644
--- a/man/man8/ip-neighbour.8
+++ b/man/man8/ip-neighbour.8
@@ -28,7 +28,9 @@ ip-neighbour \- neighbour/arp tables management.
 .BR use " ] [ "
 .BR managed " ] [ "
 .BR extern_learn " ] [ "
-.BR extern_valid " ]"
+.BR extern_valid " ] [ "
+.B  protocol
+.IR PROTO " ]"
 
 .ti -8
 .BR "ip neigh" " { " show " | " flush " } [ " proxy " ] [ " to
@@ -39,7 +41,9 @@ ip-neighbour \- neighbour/arp tables management.
 .IR STATE " ] [ "
 .B  vrf
 .IR NAME " ] ["
-.BR nomaster " ]"
+.BR nomaster " ] [ "
+.B  protocol
+.IR PROTO " ]"
 
 .ti -8
 .B ip neigh get
@@ -123,6 +127,14 @@ will not remove or invalidate the entry, but it can probe the entry and notify
 user space when the entry becomes reachable. The kernel will return the entry
 to stale state if it did not receive a confirmation after probing the entry.
 
+.TP
+.BI protocol " PROTO"
+the origin of this neighbour entry. The value can be a number or a
+string from
+.IR /etc/iproute2/rt_protos ,
+e.g.
+.BR static ", " boot ", or " dhcp.
+
 .TP
 .BI lladdr " LLADDRESS"
 the link layer address of the neighbour.
@@ -229,6 +241,14 @@ list neighbour proxies.
 .B unused
 only list neighbours which are not currently in use.
 
+.TP
+.BI protocol " PROTO"
+only list neighbour entries with the given origin protocol. The special
+value
+.B all
+matches entries with any protocol, including those with no protocol
+attribute set.
+
 .TP
 .BI nud " STATE"
 only list neighbour entries in this state.
-- 
2.56.0