diff options
Diffstat (limited to 'sbin/natd/natd.8')
| -rw-r--r-- | sbin/natd/natd.8 | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/sbin/natd/natd.8 b/sbin/natd/natd.8 index b2edece6cce1..8beff2e66b6a 100644 --- a/sbin/natd/natd.8 +++ b/sbin/natd/natd.8 @@ -1,4 +1,4 @@ -.Dd October 5, 2016 +.Dd December 6, 2024 .Dt NATD 8 .Os .Sh NAME @@ -14,6 +14,7 @@ .Op Fl deny_incoming | d .Op Fl use_sockets | s .Op Fl same_ports | m +.Op Fl udp_eim .Op Fl verbose | v .Op Fl dynamic .Op Fl in_port | i Ar port @@ -114,6 +115,26 @@ With this option, protocols such as RPC will have a better chance of working. If it is not possible to maintain the port number, it will be silently changed as per normal. +.It Fl udp_eim +When enabled, UDP packets use endpoint-independent mapping (EIM) from RFC 4787 +("full cone" NAT of RFC 3489). +All packets from the same internal address:port are mapped to the same NAT +address:port, regardless of their destination address:port. +If filtering rules allow, and if +.Em deny_incoming +is disabled, any other external address:port can +also send to the internal address:port through its mapped NAT address:port. +This is more compatible with applications, and can reduce the need for port +forwarding, but less scalable as each NAT address:port can only be +concurrently used by at most one internal address:port. +.Pp +When disabled, UDP packets use endpoint-dependent mapping (EDM) ("symmetric" +NAT). +Each connection from a particular internal address:port to different +external addresses:ports is mapped to a random and unpredictable NAT +address:port. +Two appplications behind EDM NATs can only connect to each other +by port forwarding on the NAT, or tunnelling through an in-between server. .It Fl verbose | v Do not call .Xr daemon 3 |