create host-interface name eth1 hw-addr 02:42:ac:38:00:02
set int state host-eth1 up
set int ip address host-eth1 172.56.0.2/16
ip route add 0.0.0.0/0 via 172.56.0.1 host-eth1
create gre tunnel src 172.56.0.2 dst 172.56.0.3
set int state gre0 up
set interface ip address gre0 192.168.254.254/24
ip route add 192.168.255.0/24 via 192.168.254.254 gre0
nat44 add static mapping local 172.56.0.2 external 172.56.0.2
nat44 add interface address host-eth1
set interface nat44 in gre0 out host-eth1

vpp# show int addr
gre0 (up):
192.168.254.254/24
host-eth1 (up):
172.56.0.2/16
local0 (dn):

I’ve limited numbers of entries to show you full table:

vpp# show nat44 verbose
NAT plugin mode: dynamic translations enabled
gre0 in
host-eth1 out
NAT44 pool addresses interfaces:
host-eth1
172.56.0.2
tenant VRF independent
0 busy udp ports
0 busy tcp ports
19 busy icmp ports
20 users, 1 outside addresses, 23 active sessions, 1 static mappings
Hash table in2out-ed
[623]: heap offset 131328, len 1, linear 0
0: key 216235093532883116 13229323905400832 value 0
1 active elements
1 free lists
0 linear search buckets
0 cache hits, 0 cache misses
Hash table out2in-ed
[623]: heap offset 131328, len 1, linear 0
0: key 216235093532883116 13229323905400832 value 0
1 active elements
1 free lists
0 linear search buckets
[383]: heap offset 8448, len 1, linear 0
0: key 563134670481600 value 1
[470]: heap offset 8960, len 1, linear 0
0: key 563177620154560 value 5
[524]: heap offset 8704, len 1, linear 0
0: key 371226941864108 value 3
[570]: heap offset 10880, len 1, linear 0
0: key 562951378254336 value 20
[572]: heap offset 9472, len 1, linear 0
0: key 562952019390208 value 9
[636]: heap offset 8832, len 1, linear 0
0: key 285039833135276 value 4
[655]: heap offset 10112, len 1, linear 0
0: key 562953289937920 value 14
[684]: heap offset 9344, len 1, linear 0
0: key 562950906260992 value 8
[719]: heap offset 10240, len 1, linear 0
0: key 562950108034304 value 15
[838]: heap offset 11136, len 1, linear 0
0: key 562953604250624 value 22
[862]: heap offset 9728, len 1, linear 0
0: key 562954245386496 value 11
[919]: heap offset 10368, len 1, linear 0
0: key 562951221163520 value 16
[927]: heap offset 10624, len 1, linear 0
0: key 562953447159808 value 18
[936]: heap offset 9216, len 1, linear 0
0: key 562954088230144 value 7
[937]: heap offset 10496, len 1, linear 0
0: key 562952334096128 value 17
22 active elements
1 free lists
0 linear search buckets
0 cache hits, 0 cache misses
Hash table out2in
[33]: heap offset 10240, len 1, linear 0
0: key 806753805547692 value 15
[41]: heap offset 9728, len 1, linear 0
0: key 643923005421740 value 11
[54]: heap offset 8576, len 1, linear 0
0: key 293625472759980 value 2
[56]: heap offset 10624, len 1, linear 0
0: key 760883554826412 value 18
[163]: heap offset 9472, len 1, linear 0
0: key 758250739873964 value 9
[210]: heap offset 9984, len 1, linear 0
0: key 735118046017708 value 13
[365]: heap offset 9216, len 1, linear 0
0: key 648351116703916 value 7
[372]: heap offset 10752, len 1, linear 0
0: key 764731845523628 value 19
[422]: heap offset 11136, len 1, linear 0
0: key 781082786019500 value 22
[423]: heap offset 10880, len 1, linear 0
0: key 661588205910188 value 20
[466]: heap offset 9856, len 1, linear 0
0: key 832892976511148 value 12
[473]: heap offset 10368, len 1, linear 0
0: key 756043126683820 value 16
[524]: heap offset 8704, len 1, linear 0
0: key 371226941864108 value 3
[530]: heap offset 9600, len 1, linear 0
0: key 737059371235500 value 10
[538]: heap offset 11008, len 1, linear 0
0: key 716134290569388 value 21
[636]: heap offset 8832, len 1, linear 0
0: key 285039833135276 value 4
[712]: heap offset 8448, len 1, linear 0
0: key 700659523401900 value 1
[769]: heap offset 10496, len 1, linear 0
0: key 577119084099756 value 17
[778]: heap offset 9344, len 1, linear 0
0: key 784381320902828 value 8
[985]: heap offset 8960, len 1, linear 0
0: key 619342907586732 value 5
[1012]: heap offset 10112, len 1, linear 0
0: key 781529462618284 value 14
[1015]: heap offset 9088, len 1, linear 0
0: key 710086976616620 value 6
22 active elements
1 free lists
0 linear search buckets
0 cache hits, 0 cache misses
43 list pool elements
172.56.0.3: 0 dynamic translations, 1 static translations
i2o 172.56.0.2 proto 47 fib 0
o2i 172.56.0.2 proto 47 fib 0
external host 172.56.0.3
last heard 925.62
total pkts 137, total bytes 14796
static translation

192.168.254.1: 2 dynamic translations, 0 static translations
i2o 192.168.254.1 proto icmp port 11008 fib 0
o2i 172.56.0.2 proto icmp port 16253 fib 0
external host 8.8.8.8
last heard 673.68
total pkts 151, total bytes 12684
dynamic translation

i2o 192.168.254.1 proto icmp port 13568 fib 0
o2i 172.56.0.2 proto icmp port 18995 fib 0
external host 8.8.8.8
last heard 908.63
total pkts 88, total bytes 7392
dynamic translation

172.56.0.2: 0 dynamic translations, 3 static translations
i2o 172.56.0.2 proto tcp port 3339 fib 0
o2i 172.56.0.2 proto tcp port 3339 fib 0
external host 172.56.0.2
last heard 617.19
total pkts 1, total bytes 40
static translation

i2o 172.56.0.2 proto tcp port 41297 fib 0
o2i 172.56.0.2 proto tcp port 41297 fib 0
external host 172.56.0.2
last heard 680.18
total pkts 1, total bytes 40
static translation

i2o 172.56.0.2 proto tcp port 15875 fib 0
o2i 172.56.0.2 proto tcp port 15875 fib 0
external host 172.56.0.2
last heard 750.01
total pkts 1, total bytes 40
static translation

0.44.31.180: 1 dynamic translations, 0 static translations
i2o 0.44.31.180 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 53893 fib 0
external host 190.169.0.0
last heard 909.63
total pkts 2, total bytes 168
dynamic translation

0.45.116.246: 1 dynamic translations, 0 static translations
i2o 0.45.116.246 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 44109 fib 0
external host 205.169.0.0
last heard 910.63
total pkts 2, total bytes 168
dynamic translation

0.46.203.56: 1 dynamic translations, 0 static translations
i2o 0.46.203.56 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 25801 fib 0
external host 221.169.0.0
last heard 911.63
total pkts 2, total bytes 168
dynamic translation

0.47.36.123: 1 dynamic translations, 0 static translations
i2o 0.47.36.123 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 41137 fib 0
external host 236.169.0.0
last heard 912.63
total pkts 2, total bytes 168
dynamic translation

0.48.123.189: 1 dynamic translations, 0 static translations
i2o 0.48.123.189 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 23198 fib 0
external host 251.169.0.0
last heard 913.63
total pkts 2, total bytes 168
dynamic translation

0.49.210.255: 1 dynamic translations, 0 static translations
i2o 0.49.210.255 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 42313 fib 0
external host 10.170.0.0
last heard 914.63
total pkts 2, total bytes 168
dynamic translation

0.50.44.66: 1 dynamic translations, 0 static translations
i2o 0.50.44.66 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 33781 fib 0
external host 26.170.0.0
last heard 915.63
total pkts 2, total bytes 168
dynamic translation

0.51.135.132: 1 dynamic translations, 0 static translations
i2o 0.51.135.132 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 38556 fib 0
external host 41.170.0.0
last heard 916.63
total pkts 2, total bytes 168
dynamic translation

0.52.223.198: 1 dynamic translations, 0 static translations
i2o 0.52.223.198 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 52422 fib 0
external host 56.170.0.0
last heard 917.63
total pkts 2, total bytes 168
dynamic translation

0.53.55.9: 1 dynamic translations, 0 static translations
i2o 0.53.55.9 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 48605 fib 0
external host 72.170.0.0
last heard 918.63
total pkts 2, total bytes 168
dynamic translation

0.54.144.75: 1 dynamic translations, 0 static translations
i2o 0.54.144.75 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 40623 fib 0
external host 87.170.0.0
last heard 919.63
total pkts 2, total bytes 168
dynamic translation

0.55.230.141: 1 dynamic translations, 0 static translations
i2o 0.55.230.141 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 58124 fib 0
external host 102.170.0.0
last heard 920.63
total pkts 2, total bytes 168
dynamic translation

0.56.62.208: 1 dynamic translations, 0 static translations
i2o 0.56.62.208 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 1460 fib 0
external host 117.170.0.0
last heard 921.63
total pkts 2, total bytes 168
dynamic translation

0.57.149.18: 1 dynamic translations, 0 static translations
i2o 0.57.149.18 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 34231 fib 0
external host 133.170.0.0
last heard 922.63
total pkts 2, total bytes 168
dynamic translation

0.58.237.84: 1 dynamic translations, 0 static translations
i2o 0.58.237.84 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 46681 fib 0
external host 148.170.0.0
last heard 923.64
total pkts 2, total bytes 168
dynamic translation

0.59.69.151: 1 dynamic translations, 0 static translations
i2o 0.59.69.151 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 21131 fib 0
external host 163.170.0.0
last heard 924.63
total pkts 2, total bytes 168
dynamic translation

0.60.155.217: 1 dynamic translations, 0 static translations
i2o 0.60.155.217 proto icmp port 0 fib 0
o2i 172.56.0.2 proto icmp port 25798 fib 0
external host 178.170.0.0
last heard 925.63
total pkts 2, total bytes 168
dynamic translation

static mappings:
local 172.56.0.2 external 172.56.0.2 vrf 0