[fix] "The resolved IP address corresponds to a local interface" (self hosted)

[S4r4h-O]

SMTP Envelope
Date & Time 5/16/25, 7:38 AM
MAIL FROM support@<my_domain.com>
RCPT TO
support@<my_domain.com>

Log Message
Unable to deliver email to the IP address [<vps_ip>] resolved for the Mail Exchange (MX) server of "<my_domain.com>". The resolved IP address corresponds to a local interface.

Message Headers
From "<my_domain.com>" support@<my_domain.com>
To "<my_domain.com>" support@<my_domain.com>
Subject <my_domain.com> – Email Deliverability Report Issue
Message-ID <fcb714d1-11e8-9de0-1698-e39da2f24985@<my_domain.com>>
Date Fri, 16 May 2025 10:38:08 +0000
MIME-Version 1.0
Content-Type multipart/alternative; boundary="--_NmP-11877084255b6410-Part_1"

# More detailed logs:

{
"bounce_category": "none",
"domains": [
"68263252ff31feea389d7b3f"
],
"is_empty_domains": false,
"domains_checked_at": "2025-05-16T10:38:13.158Z",
"err": {
"name": "Error",
"message": "Unable to deliver email to the IP address [<vps_ip>] resolved for the Mail Exchange (MX) server of "<my_domain.com>". The resolved IP address corresponds to a local interface.",
"stack": "Error: Unable to deliver email to the IP address [<vps_ip>] resolved for the Mail Exchange (MX) server of "<my_domain.com>". The resolved IP address corresponds to a local interface.\n at filterAddress (/app/node_modules/.pnpm/mx-connect@1.5.6/node_modules/mx-connect/lib/resolve-ip.js:63:34)\n at Array.filter ()\n at /app/node_modules/.pnpm/mx-connect@1.5.6/node_modules/mx-connect/lib/resolve-ip.js:100:39\n at Array.forEach ()\n at /app/node_modules/.pnpm/mx-connect@1.5.6/node_modules/mx-connect/lib/resolve-ip.js:98:29\n at process.processTicksAndRejections (node:internal/process/task_queues:95:5)",
"code": "InvalidIpAddress",
"response": "DNS Error: Unable to deliver email to the IP address [<vps_ip>] resolved for the Mail Exchange (MX) server of "<my_domain.com>". The resolved IP address corresponds to a local interface.",
"category": "dns",
"isCodeBug": false
},
"date": "2025-05-16T10:38:08.000Z",
"subject": "<my_domain.com> – Email Deliverability Report Issue",
"keywords": [
"b32812778b",
"b11d461d8b",
"66b6d75185"
],
"text_message": "Unable to deliver email to the IP address [<vps_ip>] resolved for the Mail Exchange (MX) server of "<my_domain.com>". The resolved IP address corresponds to a local interface.",
"message": "Unable to deliver email to the IP address [<vps_ip>] resolved for the Mail Exchange (MX) server of "<my_domain.com>". The resolved IP address corresponds to a local interface.",
"meta": {
"user": "682631ffff31feea389d7aba",
"email": "68271591bf585ff4865c62f6",
"domains": [
"68263252ff31feea389d7b3f"
],
"session": {
"envelope": {
"mailFrom": {
"address": "support@<my_domain.com>"
},
"rcptTo": [
{
"address": "support@<my_domain.com>"
}
]
},
"headers": {
"From": ""<my_domain.com>" <support@<my_domain.com>",
"To": ""<my_domain.com>" <support@<my_domain.com>",
"Subject": "<my_domain.com> – Email Deliverability Report Issue",
"Message-ID": "<fcb714d1-11e8-9de0-1698-e39da2f24985@<my_domain.com>",
"Date": "Fri, 16 May 2025 10:38:08 +0000",
"MIME-Version": "1.0",
"Content-Type": "multipart/alternative; boundary="--_NmP-11877084255b6410-Part_1""
},
"originalFromAddress": "support@<my_domain.com>"
},
"err": {
"name": "Error",
"message": "Unable to deliver email to the IP address [<vps_ip>] resolved for the Mail Exchange (MX) server of "<my_domain.com>". The resolved IP address corresponds to a local interface.",
"stack": "Error: Unable to deliver email to the IP address [<vps_ip>] resolved for the Mail Exchange (MX) server of "<my_domain.com>". The resolved IP address corresponds to a local interface.\n at filterAddress (/app/node_modules/.pnpm/mx-connect@1.5.6/node_modules/mx-connect/lib/resolve-ip.js:63:34)\n at Array.filter ()\n at /app/node_modules/.pnpm/mx-connect@1.5.6/node_modules/mx-connect/lib/resolve-ip.js:100:39\n at Array.forEach ()\n at /app/node_modules/.pnpm/mx-connect@1.5.6/node_modules/mx-connect/lib/resolve-ip.js:98:29\n at process.processTicksAndRejections (node:internal/process/task_queues:95:5)",
"code": "InvalidIpAddress",
"response": "DNS Error: Unable to deliver email to the IP address [<vps_ip>] resolved for the Mail Exchange (MX) server of "<my_domain.com>". The resolved IP address corresponds to a local interface.",
"category": "dns"
},
"level": "error",
"app": {
"name": "forward-email",
"version": "1.0.3",
"node": "v20.19.1",
"environment": "production",
"hostname": "smtp.<my_domain.com>",
"ip": "<vps_ip>",
"pid": 1,
"cluster": {
"isPrimary": true,
"isWorker": false,
"schedulingPolicy": 2
},
"os": {
"arch": "x64",
"cpus": [
{
"model": "AMD EPYC 9354P 32-Core Processor",
"speed": 0,
"times": {
"user": 819920,
"nice": 48080,
"sys": 454250,
"idle": 8924150,
"irq": 0
}
},
{
"model": "AMD EPYC 9354P 32-Core Processor",
"speed": 0,
"times": {
"user": 809820,
"nice": 44380,
"sys": 425010,
"idle": 9088920,
"irq": 0
}
}
],
"endianness": "LE",
"freemem": 6578036736,
"priority": 0,
"homedir": "/root",
"hostname": "smtp.<my_domain.com>",
"loadavg": [
0.77,
0.41,
0.6
],
"network_interfaces": {
"lo": [
{
"address": "127.0.0.1",
"netmask": "255.0.0.0",
"family": "IPv4",
"mac": "00:00:00:00:00:00",
"internal": true,
"cidr": "127.0.0.1/8"
},
{
"address": "::1",
"netmask": "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff",
"family": "IPv6",
"mac": "00:00:00:00:00:00",
"internal": true,
"cidr": "::1/128",
"scopeid": 0
}
],
"eth0": [
{
"address": "<vps_ip>",
"netmask": "255.255.255.0",
"family": "IPv4",
"mac": "fc:e8:d4:b1:88:d6",
"internal": false,
"cidr": "<vps_ip>/24"
},
{
"address": "2a02:4780:14:4612::1",
"netmask": "ffff:ffff:ffff::",
"family": "IPv6",
"mac": "fc:e8:d4:b1:88:d6",
"internal": false,
"cidr": "2a02:4780:14:4612::1/48",
"scopeid": 0
},
{
"address": "fe80::fee8:d4ff:feb1:88d6",
"netmask": "ffff:ffff:ffff:ffff::",
"family": "IPv6",
"mac": "fc:e8:d4:b1:88:d6",
"internal": false,
"cidr": "fe80::fee8:d4ff:feb1:88d6/64",
"scopeid": 2
}
]
},
"platform": "linux",
"release": "5.15.0-140-generic",
"tmpdir": "/tmp",
"totalmem": 8322453504,
"type": "Linux",
"uptime": 11078.15,
"user": {
"uid": 0,
"gid": 0,
"username": "root",
"homedir": "/root",
"shell": "/bin/bash"
},
"version": "#150-Ubuntu SMP Sat Apr 12 06:00:09 UTC 2025"
},
"worker_threads": {
"isMainThread": false,
"resourceLimits": {
"maxYoungGenerationSizeMb": 48,
"maxOldGenerationSizeMb": 2048,
"codeRangeSizeMb": 0,
"stackSizeMb": 4
},
"threadId": 1,
"workerData": {
"job": {
"name": "send-emails",
"interval": 30000,
"timeout": 0,
"path": "/app/jobs/send-emails.js",
"timezone": "local"
}
}
}
}
},
"created_at": "2025-05-16T10:38:12.963Z",
"is_restricted": true,
"id": "68271594183cf1756b69cd90",
"object": "log",
"updated_at": "2025-05-16T10:38:12.963Z"
}

[shaunwarman]

From the mx container, if I dig the DOMAIN or hostname then I should get back the VPS IP. Are you getting a response of 127.0.0.1 / loopback address? You may need to add a hostname or label configuration on the VPS provider to ensure that the hostname binds and resolves to the VPS IP even from within the host and container (using dockers network mode host)

[titanism]

To fix this, you need to set blockLocalAddresses to false for self-hosting most likely

https://www.npmjs.com/package/mx-connect#:~:text=blockLocalAddresses%20(boolean%2C%20defaults

forwardemail.net/helpers/get-transporter.js

Line 234 in a9eef13

blockLocalAddresses: env.NODE_ENV !== 'test',

cc @shaunwarman