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* [iptables PATCH] extensions: man: Add a note about route_localnet sysctl
       [not found] <CGME20250821103945eucas1p211e02560c0125f4f0eddae86798b9a01@eucas1p2.samsung.com>
@ 2025-08-21 10:39 ` Łukasz Stelmach
  2025-08-21 14:22   ` Florian Westphal
  0 siblings, 1 reply; 2+ messages in thread
From: Łukasz Stelmach @ 2025-08-21 10:39 UTC (permalink / raw)
  To: netfilter-devel; +Cc: Marek Szyprowski, Łukasz Stelmach

See ip_route_input_slow() in net/ipv4/route.c in the Linux
kernel sources.

Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
---
 extensions/libxt_DNAT.man | 4 ++++
 1 file changed, 4 insertions(+)

diff --git extensions/libxt_DNAT.man extensions/libxt_DNAT.man
index 090ecb42..cbfa5478 100644
--- extensions/libxt_DNAT.man
+++ extensions/libxt_DNAT.man
@@ -23,6 +23,10 @@ its value is used as offset into the mapping port range. This allows one to crea
 shifted portmap ranges and is available since kernel version 4.18.
 For a single port or \fIbaseport\fP, a service name as listed in
 \fB/etc/services\fP may be used.
+If \fIipaddr\fP is an IPv4 loopback address (i.e. 127.0.0.0/8) the
+"net.ipv4.conf.*.route_localnet" sysctl for the input interface needs
+to be set to 1. Otherwise packets will be dropped by the routing code
+as "martians".
 .TP
 \fB\-\-random\fP
 Randomize source port mapping (kernel >= 2.6.22).
-- 
2.39.5


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [iptables PATCH] extensions: man: Add a note about route_localnet sysctl
  2025-08-21 10:39 ` [iptables PATCH] extensions: man: Add a note about route_localnet sysctl Łukasz Stelmach
@ 2025-08-21 14:22   ` Florian Westphal
  0 siblings, 0 replies; 2+ messages in thread
From: Florian Westphal @ 2025-08-21 14:22 UTC (permalink / raw)
  To: Łukasz Stelmach; +Cc: netfilter-devel, Marek Szyprowski

Łukasz Stelmach <l.stelmach@samsung.com> wrote:
> See ip_route_input_slow() in net/ipv4/route.c in the Linux
> kernel sources.

Applied.

^ permalink raw reply	[flat|nested] 2+ messages in thread

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     [not found] <CGME20250821103945eucas1p211e02560c0125f4f0eddae86798b9a01@eucas1p2.samsung.com>
2025-08-21 10:39 ` [iptables PATCH] extensions: man: Add a note about route_localnet sysctl Łukasz Stelmach
2025-08-21 14:22   ` Florian Westphal

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