Dear ServerFault community
I have a problem with my WireGuard Tunnel overall configuration.
I have an OVH VPS with 4 public IPs (MY_PUBLIC) acting as a WireGuard server and forwarding all the traffic (and ports) to my EdgeRouter-X router (192.168.255.1) (which acts as a WireGuard client) and that, then, forwards it to my Debian server (192.168.255.10).
The problem is that when on the Debian server I try to bind to any of the OVH VPS WireGuard's public IPs (MY_PUBLIC) [I tried making Apache bind to them, along with MariaDB and Docker but nothing] I get a bind error telling me that it is not possible.
bind: cannot assign requested address.
After some research I found this:
The message “Cannot assign requested address” suggests that the hostname/IP you are trying to bind does not resolve to a local network interface.
From online research this seems to suggest a NAT being somewhere between the VPS and the server. I am a newbie with networks and I have no idea how to solve this issue.
This is a major issue as the server can only use those IPs binding to 0.0.0.0.
My ER-X configuration:
firewall {
all-ping enable
broadcast-ping disable
group {
address-group MY_PUBLIC { // OVH VPS's IPs
address 92.CENSORED.CENSORED.108
address 149.CENSORED.CENSORED.64
address 37.CENSORED.CENSORED.244
address 149.CENSORED.CENSORED.244
}
}
ipv6-name WANv6_IN {
default-action drop
description "WAN inbound traffic forwarded to LAN"
enable-default-log
rule 10 {
action accept
description "Allow established/related sessions"
state {
established enable
related enable
}
}
rule 20 {
action drop
description "Drop invalid state"
state {
invalid enable
}
}
}
ipv6-name WANv6_LOCAL {
default-action drop
description "WAN inbound traffic to the router"
enable-default-log
rule 10 {
action accept
description "Allow established/related sessions"
state {
established enable
related enable
}
}
rule 20 {
action drop
description "Drop invalid state"
state {
invalid enable
}
}
rule 30 {
action accept
description "Allow IPv6 icmp"
protocol ipv6-icmp
}
rule 40 {
action accept
description "allow dhcpv6"
destination {
port 546
}
protocol udp
source {
port 547
}
}
}
ipv6-receive-redirects disable
ipv6-src-route disable
ip-src-route disable
log-martians enable
modify wireguard_route {
rule 5 {
action modify
destination {
group {
address-group MY_PUBLIC
}
}
modify {
table main
}
}
rule 7 {
action modify
destination {
address 172.16.1.0/24
}
modify {
table main
}
}
rule 10 {
action modify
description wireguard-vpn
modify {
table 1
}
source {
address 192.168.255.0/24
}
}
}
name WAN_IN {
default-action drop
description "WAN to internal"
rule 10 {
action accept
description "Allow established/related"
state {
established enable
related enable
}
}
rule 20 {
action drop
description "Drop invalid state"
state {
invalid enable
}
}
}
name WAN_LOCAL {
default-action drop
description "WAN to router"
rule 10 {
action accept
description "Allow established/related"
state {
established enable
related enable
}
}
rule 20 {
action drop
description "Drop invalid state"
state {
invalid enable
}
}
rule 30 {
action accept
description openvpn
destination {
port 1194
}
protocol udp
}
}
receive-redirects disable
send-redirects enable
source-validation disable
syn-cookies enable
}
interfaces {
ethernet eth0 {
address dhcp
description Internet
dhcpv6-pd {
pd 0 {
interface eth1 {
service dhcpv6-stateful
}
interface eth2 {
service dhcpv6-stateful
}
interface eth3 {
service dhcpv6-stateful
}
interface switch0 {
host-address ::1
service slaac
}
prefix-length /64
}
rapid-commit enable
}
duplex auto
firewall {
in {
ipv6-name WANv6_IN
name WAN_IN
}
local {
ipv6-name WANv6_LOCAL
name WAN_LOCAL
}
}
ipv6 {
address {
autoconf
}
dup-addr-detect-transmits 1
}
speed auto
}
ethernet eth1 {
description Local
duplex auto
speed auto
}
ethernet eth2 {
description Local
duplex auto
speed auto
}
ethernet eth3 {
description Local
duplex auto
speed auto
}
ethernet eth4 {
description Local
duplex auto
poe {
output off
}
speed auto
}
loopback lo {
}
openvpn vtun0 {
mode server
server {
name-server 192.168.255.1
push-route 192.168.255.0/24
subnet 172.16.1.0/24
}
tls {
ca-cert-file /config/auth/cacert.pem
cert-file /config/auth/server.pem
dh-file /config/auth/dh.pem
key-file /config/auth/server.key
}
}
switch switch0 {
address 192.168.255.1/24
description Local
firewall {
in {
modify wireguard_route
}
}
mtu 1500
switch-port {
interface eth1 {
}
interface eth2 {
}
interface eth3 {
}
interface eth4 {
}
vlan-aware disable
}
}
wireguard wg0 {
address 10.0.0.2/30
description Wireguard
listen-port 51821
mtu 1420
peer CENSORED+CENSORED+CENSORED= {
allowed-ips 0.0.0.0/0
endpoint 92.CENSORED.CENSORED.108:51821
persistent-keepalive 25
preshared-key /config/auth/wg-preshared.key
}
private-key /config/auth/wg.key
route-allowed-ips false
}
}
port-forward {
auto-firewall enable
hairpin-nat enable
lan-interface switch0
rule 1 {
description "Allow ALL"
forward-to {
address 192.168.255.10
}
original-port 1-65535
protocol tcp_udp
}
wan-interface wg0
}
protocols {
static {
table 1 {
description "table to force wg0:aws"
interface-route 0.0.0.0/0 {
next-hop-interface wg0 {
}
}
route 0.0.0.0/0 {
blackhole {
distance 255
}
}
}
}
}
service {
dhcp-server {
disabled false
hostfile-update disable
shared-network-name LAN-X {
authoritative disable
subnet 192.168.255.0/24 {
default-router 192.168.255.1
dns-server 192.168.255.1
lease 86400
start 192.168.255.2 {
stop 192.168.255.254
}
static-mapping iDRAC {
ip-address 192.168.255.120
mac-address CENSORED:CENSORED:CENSORED:CENSORED:CENSORED:CENSORED
}
static-mapping node2 {
ip-address 192.168.255.10
mac-address CENSORED:CENSORED:CENSORED:CENSORED:CENSORED:CENSORED
}
}
}
static-arp disable
use-dnsmasq disable
}
dns {
forwarding {
cache-size 150
listen-on switch0
listen-on vtun0
}
}
gui {
http-port 80
https-port 443
older-ciphers enable
}
nat {
rule 5001 {
description wireguard-nat
log disable
outbound-interface wg0
protocol all
source {
address 192.168.255.0/24
}
type masquerade
}
rule 5002 {
description "masquerade for WAN"
log disable
outbound-interface eth0
protocol all
type masquerade
}
}
ssh {
port 22
protocol-version v2
}
unms {
}
}
system {
analytics-handler {
send-analytics-report false
}
crash-handler {
send-crash-report false
}
host-name EdgeRouter-X-5-Port
login {
user ubnt {
authentication {
encrypted-password CENSORED
}
level admin
}
}
ntp {
server 0.ubnt.pool.ntp.org {
}
server 1.ubnt.pool.ntp.org {
}
server 2.ubnt.pool.ntp.org {
}
server 3.ubnt.pool.ntp.org {
}
}
offload {
hwnat enable
ipsec enable
}
syslog {
global {
facility all {
level notice
}
facility protocols {
level debug
}
}
}
time-zone UTC
}
My OVH VPS's WG config:
[Interface]
Address = 10.0.0.1/30
ListenPort = 51821
PrivateKey = CENSORED
### Client vpn
[Peer]
PublicKey = CENSORED
PresharedKey = CENSORED
AllowedIPs = 10.0.0.2/30
My OVH IPTables:
# Generated by iptables-save v1.8.7 on Sun Jan 9 11:04:33 2022
*filter
:INPUT ACCEPT [971:145912]
:FORWARD ACCEPT [920:137172]
:OUTPUT ACCEPT [637:108812]
:f2b-sshd - [0:0]
COMMIT
# Completed on Sun Jan 9 11:04:33 2022
# Generated by iptables-save v1.8.7 on Sun Jan 9 11:04:33 2022
*nat
:PREROUTING ACCEPT [133:6792]
:INPUT ACCEPT [61:2272]
:OUTPUT ACCEPT [3:228]
:POSTROUTING ACCEPT [66:4011]
-A PREROUTING -i ens3 -p udp -m multiport --dports 1000:51820 -j DNAT --to-destination 10.0.0.2
-A PREROUTING -i ens3 -p udp -m multiport --dports 51822:65534 -j DNAT --to-destination 10.0.0.2
-A PREROUTING -i ens3 -p tcp -m multiport --dports 51822:65534 -j DNAT --to-destination 10.0.0.2
-A PREROUTING -i ens3 -p tcp -m multiport --dports 1000:51820 -j DNAT --to-destination 10.0.0.2
-A PREROUTING -i ens3 -p tcp -m multiport --dports 21,22,80,25,995,110,443,465,993,143 -j DNAT --to-destination 10.0.0.2
-A PREROUTING -i ens3 -p udp -m multiport --dports 21,22,80,25,995,110,443,465,993,143 -j DNAT --to-destination 10.0.0.2
-A POSTROUTING -o ens3 -j MASQUERADE
COMMIT
# Completed on Sun Jan 9 11:04:33 2022
Just for troubleshooting I tried binding to my Office IP which, as expected and wanted, does not work as behind ER-X's WireGuard Tunnel.
Here are some topics that helped me set my current WireGuard structure UP: https://community.ui.com/questions/EdgeRouter-X-as-WireGuard-Client-Forward-ports-from-WG-tunnel-to-LAN/f19957fb-70be-485f-832d-381c6ea4b306
https://community.ui.com/questions/EdgeRouter-X-as-a-WireGuard-client-with-port-forwarding-or-User-IP-is-shown-to-be-WireGuard-tunnels/2a8b19ab-ac0c-48ed-b367-afd3914de9c2
Thank you in advance for your help!
