Free tools Windows power users keep installed
One-click scans. No signup required.
iTechGuides is reader-supported. When you buy through links on our site, we may earn an affiliate commission. As an Amazon Associate I earn from qualifying purchases. Learn more
Need a server to try this on? Antihost offers Linux VPS plans with NVMe storage, full root access and a 14-day free trial.
For an Ubuntu host that only needs to send alerts, cron output, and application mail, install the exim4 package and select mail sent by smarthost; no local mail in Debian’s configuration wizard. Enter the relay host (and port when needed), configure authentication and TLS if the relay requires them, then regenerate the configuration and restart Exim. Verify the handoff with the queue commands and Exim logs.
What send-only Exim mode does
Exim can deliver mail directly to recipient domains or hand messages to another SMTP server. A send-only Ubuntu machine normally should use the smarthost configuration with local mail disabled. In this mode, mail generated on the host is forwarded to a remote SMTP relay instead of being delivered locally, and the machine is not configured as the mail server for a local email domain.
A smarthost is especially appropriate for a server with a dynamic or otherwise untrusted public IP address. Many receiving systems limit or block direct SMTP delivery from dynamic-address ranges, so using a relay avoids requiring this host to build direct-delivery reputation and accept Internet mail. The relay still controls authentication, sender policy, rate limits, and final delivery.
- Outgoing notifications: suitable for system mail, monitoring alerts, backups, and applications that submit through
/usr/sbin/sendmail. - No normal inbound service: the host is not intended to receive mail for external domains.
- Relay dependency: delivery depends on the relay being reachable and accepting the credentials and sender address.
This is a routing choice, not merely a switch that turns off one listening socket. Exim still accepts locally submitted messages, places them in its queue, and applies its routers and transports. The destination of those messages is the configured smarthost. Consequently, a local application can often continue using the standard sendmail-compatible interface without knowing the relay’s username, password, or hostname.
#1 Best Overall
- Powerful Turbo Fan:CAGIWIRU Electric Air Duster have reached speed up to 130000RPM,Can efficient remove dust and debris.With LED light and Three Adjustable Speed to meet with different cleaning tasks.
- With Attached USB C Fasting Charging cable.Charing 3 hours,Enjoy up to 240 minutes of use on the lowest setting, For third speed can use for 25mins.with four charging options to meet with your needs.
- Wide Application: attached 5 different nozzles,making it suitable for a variety of scenes, such as car,pet, pc, keyboards, and other electronic devices. It also serves for office and home clean duster.
- Handy Design & Portable:Cordless air duster electric nozzle is Light weight and small size, design and comfortable to hold and space saving, convenient to carry around. You can put it in your room or inside the car without taking up space.
- Economical &Reusable: Built durable materials with a long-lasting battery,our CAGIWIRU air duster it's a sustainable alternative to disposable air cans.
Before installing
- Use an Ubuntu account that can run
sudo. - Obtain the SMTP relay’s hostname or IP address and its required port. The standard SMTP submission port is not assumed; use the value specified by the relay administrator.
- Determine whether the relay requires SMTP authentication, and which authentication method, username, password, sender addresses, and TLS policy it permits.
- Ensure the server can resolve the relay hostname and that outbound firewall rules allow connections to the required SMTP port.
- Choose a sender address the relay allows. A relay may reject mail when the envelope or header sender is outside its approved domains.
Do not put real passwords in a public document, in a command copied to shell history, or in a world-readable configuration file. Apply the relay’s credential-storage instructions and restrict access to any Exim authentication file.
Clarify the relay’s policy before you start. Some relays authorize a specific account, some authorize the server’s source address, and some require both an approved sender domain and authenticated submission. Ask whether the relay expects ordinary SMTP with an upgrade to TLS or another encryption mode, and record the exact hostname because certificate validation depends on using the correct name rather than an unrelated IP address.
Do these 3 things before closing this tab:
1Repair Windows errors before they cause bigger problems2Fix the driver behind crashes, sound loss and screen glitches3Clear out junk files and repair common Windows errorsAlso decide whether you want one generated Exim configuration file or Debian’s split-file layout. The choice affects where you inspect source fragments, but it does not change the smarthost concept. The wizard supports either arrangement.
Install the Exim4 package
Refresh Ubuntu’s package index and install Exim4:
sudo apt update
sudo apt install exim4The package installation provides Exim and Debian’s configuration system. If a configuration dialog appears during installation, you can complete it there or run the reconfiguration wizard explicitly in the next step.
Use the package supplied by Ubuntu rather than downloading an unrelated Exim build. Debian’s packaging supplies the configuration answers, templates, service integration, queue handling, and the update-exim4.conf command used later. Keeping those pieces together makes subsequent reconfiguration predictable.
Open Debian’s Exim configuration wizard
Run:
sudo dpkg-reconfigure exim4-configThe wizard asks how Exim should be configured and whether to keep one generated configuration file or use split files under /etc/exim4/conf.d. Either layout is supported by Debian’s packaging. The important choice for a send-only host is the general mail configuration type.
If you are correcting an existing installation, this command is also the safest way to revisit the principal answers. It prevents an old Internet-site choice or an obsolete relay value from being mistaken for the active design. Work through the prompts carefully instead of assuming that restarting the service alone will apply a new answer.
Select “mail sent by smarthost; no local mail”
At the general configuration prompt, choose mail sent by smarthost; no local mail. This option is intended for a client system that is not responsible for a local email domain. Locally generated messages are submitted to the configured smarthost rather than being routed as local-domain mail.
Do not select a mode merely because it sounds more powerful:
| Wizard choice | Use it when | Trade-off |
|---|---|---|
| Mail sent by smarthost; no local mail | The Ubuntu machine only needs outbound notifications and another SMTP server will deliver them. | Requires a reachable relay and, when required, valid credentials and permitted sender addresses. It avoids direct-delivery reputation and reduces inbound exposure. |
| Internet site | The host has a stable, correctly configured public mail identity and is deliberately intended to deliver directly to recipient domains. | Requires substantially more DNS, reputation, TLS, queue, abuse, and inbound-mail administration. It is not the usual send-only choice. |
| Local delivery only | Messages must remain on this Ubuntu host. | Does not deliver mail to remote recipients and therefore does not meet a send-only-to-the-Internet requirement. |
The phrase “no local mail” can be misunderstood. It does not mean that Exim rejects every message generated on the machine. It means the host is not responsible for delivering mail for a local email domain; locally generated mail is routed onward through the smarthost. If an application submits a message and it appears in the queue, that is expected behavior while Exim is waiting for the relay or retrying a temporary failure.
Rank #2
- Screen Cleaner is Your Screen’s New Bestfriend! - EVEO is proud to present a screen cleaner that’s perfectly suited for your TV. Meet your new screen cleaner, computer screen cleaner, laptop cleaner, iPad cleaner, Macbook,tv cleaner or any other electronic device. Our screen cleaner spray and wipe along with the included plush microfiber cloth, easily removes dust, fingerprints & other smudges on the screen’s surface. Clean effectively for a streak-free screen
- Gentle on your Screens - Our screen cleaner spray and wipes is compatible to be used even for the most sensitive LCD, LED, CRT, and OLED screens in proper use. Be at ease knowing that this product is compatible with all the major brands: LG, SONY, Samsung, Sharp, iPad, iPhone, Android screens, Kindle, PC monitors - we’ve got you covered! Can be used as LCD screen cleaner, tv cleaner, smart tv screen cleaner, and more
- Premium Super Soft Plush Microfiber Cloth - Included in this efficient screen cleaning kit. This screen cleaner spray and wipe has our signature plush microfiber cloth specially designed to comply with screens and monitors and leave them streak-free. Has been shown to effectively absorbs stubborn stains, zero streaks, and no fiber shedding. Always use this together with our screen cleaner for the best results
- Easy-to-Use Screen Cleaner Kit + microfiber cleaning cloth - The EVEO Screen Cleaning Kit will easily be your new favorite tool when it comes to taking care of the things you love most, quick and easy solution for a streak-free screen. Simply screw on the sprayer gun on the screen cleaner bottle. Spray the cleaning liquid onto the microfiber cloth, then wipe the screen until desired cleanliness & shine is achieved.
- Quality Screen Care Kit Worth Purchasing - Enjoy a convenient Screen Cleaner anytime, anywhere you need it. Your satisfaction is our top priority. We stand behind the quality of our products and that’s why, you shouldn’t be worrying at all. We manufacture the Best Screen Cleaner. and can be used for laptop cleaning kit, laptop screen cleaner, tv screen cleaner for smart tv. MacBook screen cleaner, monitor cleaner or screen cleaner spray for electronic devices with microfiber cleaning cloth
Conversely, do not add the recipient’s external domain to a local-domain list simply to make a test work. In a send-only design, external domains should be handled by the smarthost route. Marking one as local can make Exim attempt local delivery and produce confusing results.
Enter the smarthost and port
When the wizard requests the outgoing relay, enter its fully qualified hostname or IP address. Debian’s Exim configuration accepts a non-standard port by appending two colons to the host, for example:
smtp.example.net::587The example uses port 587 only to demonstrate the syntax. Use the exact host, port, and encryption requirements supplied by the relay operator. A relay that requires implicit TLS, a particular submission port, or a restricted source network may not accept a generic SMTP connection.
Windows Errors? Fix Them Before They Spread
Repair common Windows errors and clear accumulated junk for a smoother, more stable PC - no reinstall needed.Free scan · no reinstallCrashes, No Sound, or Screen Glitches?
Random freezes, missing sound and display glitches usually trace back to one bad driver. Find and replace yours safely.Free scan · under a minuteContinue through the remaining wizard questions with values that match the relay’s policy. In particular, do not list external recipient domains as local domains when the purpose is to forward them through the smarthost. Adding a domain as local changes routing behavior and can cause Exim to attempt local delivery instead of relay submission.
Enter the relay exactly as documented, including its fully qualified name and the two-colon port notation when a non-default port is required. A hostname typo, an omitted port separator, or a port blocked by the egress firewall can all look like an authentication problem because Exim never reaches the stage where credentials are exchanged. If the provider supplies separate hostnames for submission and receiving mail, use the submission hostname.
The relay address is a destination for outbound SMTP, not a DNS record that turns this Ubuntu host into a public mail server. You do not need to publish an inbound MX record for the Ubuntu machine merely because Exim is installed in smarthost mode.
Configure SMTP authentication and TLS
If the relay accepts unauthenticated mail from this server’s network, no username or password is needed. If it requires SMTP authentication, configure Exim’s authentication mechanism and credentials according to the relay’s instructions. The exact mechanism and credential file arrangement depend on the relay and the Debian Exim configuration being used, so copy only the settings it documents.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Password-based authentication must be protected by TLS. Confirm all of the following before sending credentials:
- The relay advertises or otherwise requires the TLS mode expected by your Exim configuration.
- The selected port matches that TLS mode; do not assume that a port number alone enables encryption.
- The relay’s certificate and hostname can be validated by the system’s TLS trust configuration.
- The account is authorized to use the sender address and recipient destinations you intend to submit.
Keep authentication data out of shell history and source control. After saving credentials, check their ownership and permissions using the relay administrator’s security requirements, and avoid pasting secrets into diagnostic output.
Authentication and sender authorization are separate checks. A valid password may still be rejected if the envelope sender is not approved, if the account is not enabled for SMTP submission, or if the relay limits which recipients the account may use. When a provider gives a list of permitted sender addresses, test with one of those addresses rather than an arbitrary address that only looks plausible.
Do not “fix” a failed login by turning off encryption. Unencrypted password authentication exposes the credential to anyone able to observe the connection. Instead, compare the relay’s documented TLS mode, port, certificate name, and authentication mechanism with the values in the Exim transport and authenticator configuration.
The Tool Desk
Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Rank #3
- 【Large size】：Measuring 800 x 300 mm/ 31. 5×12 inches, which is wider and taller than others. Large mouse pad can perfectly fit your keyboard and mouse of any size, and there is also ample space for peripherals such as phones, tablets, etc.
- 【LED backlight mouse pad】：Blade Hawks RGB mouse pad provides 7 static modes and 7 dynamic modes will give you the options you are looking for. Power-off memory function remembers the last lighting mode you selected. The super glow fiber Chroma will give you a colorful gaming setup that you want.
- 【Anti-slip rubber base】：Made from Natural rubber, this gaming mousepad will firmly grip your desktop, allowing you to enjoy the ultimate precision in the games you are most passionate about. It also comes with a texture that enhances this ability even further.
- 【Smooth and waterproof surface】: Micro-textured cloth surface, for extremely precise mouse control and a smooth movement. When liquid splashes on the gaming mouse pad, it forms water droplets and slides down. Will not delay your work or gameplay.
- 【Plug and play】: This mouse and keyboard pad is powered by USB, plug and play, no driver required. One button control light modes. Press one time to change the lighting mode, press twice to change the brightness, press and hold about 3 seconds turn ON/OFF.
Generate and activate Exim’s configuration
Debian stores answers and templates separately from the active generated configuration. After completing the wizard, build the active file and restart the service:
sudo update-exim4.conf
sudo systemctl restart exim4update-exim4.conf assembles the active Exim configuration from Debian-managed answers and templates. Run it again whenever you change the source configuration. Do not hand-edit the generated output: a later regeneration can overwrite manual changes, and the result may no longer reflect the wizard’s settings.
If you selected split configuration, source fragments are under /etc/exim4/conf.d. The wizard’s stored answers are represented in Debian’s Exim configuration files, including /etc/exim4/update-exim4.conf.conf. Inspect those source files when diagnosing a wrong mode or relay value, then regenerate and restart rather than editing generated output.
Regeneration and restart are distinct operations. The first writes a new active configuration; the second causes the running Exim service to use it. If you change a relay hostname, port, authentication file, or TLS-related setting and perform only one of these steps, the running process may continue using old values. Repeat both steps after source changes.
Likewise, avoid editing a generated file merely because its contents appear easier to understand. Debian’s templates and stored answers are the durable inputs. A package update, another wizard run, or the next regeneration can replace generated edits without warning.
Send a test message and verify the handoff
Submit a message from the local host with an installed mail client such as mail, or use an application that invokes /usr/sbin/sendmail. The test should use a recipient address outside the Ubuntu host so that it exercises the smarthost route.
Use a sender address that the relay permits, and make the subject distinctive enough to find at the destination. A successful local command only proves that Exim accepted the submission; it does not prove that the remote relay accepted or finally delivered the message.
Use Exim’s queue and log tools to determine what happened:
Quick wins for a faster PC:
Clear out junk files and repair common Windows errorsFree Scan →Scan for outdated or missing drivers - takes under a minuteDriver Scan →exim -bp
exim -qff
sudo tail -f /var/log/exim4/mainlog
sudo tail -f /var/log/exim4/rejectlogexim -bplists messages currently queued. A message that disappears after successful handoff has normally been accepted by the next delivery stage; confirm final receipt at the destination as well.exim -qffforces a queue run, including messages that would otherwise wait for their retry time. Use it when you have corrected a transient problem and want Exim to attempt delivery again./var/log/exim4/mainlogrecords delivery attempts, deferrals, and SMTP responses./var/log/exim4/rejectlogrecords messages or connections rejected by Exim’s policy.
A send-only setup should show the message being handed to the configured smarthost. It should not behave as a general inbound server for external domains. A successful local submission alone is not proof of final delivery: the relay can still reject, defer, or filter the message later.
Read the log while submitting the test so you can correlate the queue ID, relay connection, SMTP response, and final queue state. A temporary deferral normally leaves the message queued for a later retry. A permanent rejection requires correcting the stated policy or configuration problem rather than repeatedly forcing the same queue run.
After the relay accepts the message, verify receipt at the destination and inspect any bounce or filtering notice. The relay may apply its own sender policy, rate limits, or content controls after Exim has handed the message over. Those decisions are outside the local queue, so destination confirmation is an important final check.
Rank #4
- 【Softer and More Comfortable】Vaydeer wrist rest has unique diamond pattern, which is the combination of softness and aesthetics. The materials of wrist rest are improved into higher quality memory foam and covered with silky smooth lycra. The computer wrist rest makes you as comfortable and cushiony as like rest your wrists on clouds.
- 【Ergonomic Wrist Saver】The wrist rests for keyboard and mouse comes with a 17.32×3.15×0.83 inch keyboard wrist pad and a 5.94×3.15×0.83 inch mouse wrist support. Based on ergonomic design, the unique concave shape is the perfect fit for your wrist joints. The wrist rest pad fits most computer keyboards and laptops, improve hand and wrist posture, release your wrist and arm stress.
- 【Non-Slip Rubber Bottom】Featuring an anti-skid silicone base on the bottom, this wrist keyboard support stays firmly in place on your desk, preventing the padding from sliding around, ensuring stable and consistent wrist support during extended computer sessions.
- 【Better Experience & Pain Relief】Our keyboard arm rest is beneficial to alleviate the soreness caused by direct contact and friction between your arm and a hard desk surface, reducing the risk of wrist fatigue or carpal tunnel. The soft texture of memory foam can evenly distribute the pressure around your wrists and provide good support with just enough give.
- 【Helpful in Multiple Scenarios】Whether you're working, studying, writing, typing, gaming, this keyboard and mouse rest combo is an essential accessory to add comfort and support to your hands and wrists. It’s also a great gift for men, women, family, friend, coworker, gamer, teacher, etc.
Troubleshoot deferred or rejected mail
Exim is using the wrong mode
Re-run the wizard:
sudo dpkg-reconfigure exim4-configChoose mail sent by smarthost; no local mail, verify the relay value, then regenerate and restart:
Recommended Free Tools
sudo update-exim4.conf
sudo systemctl restart exim4Check the Debian-managed answers, including /etc/exim4/update-exim4.conf.conf, rather than relying on a generated file that may be replaced during the next update.
The relay hostname or port cannot be reached
Read the exact SMTP response in /var/log/exim4/mainlog. Verify DNS resolution for the relay host, outbound firewall rules, routing, and the port supplied by the relay administrator. A typo in the host or the ::port syntax can prevent Exim from connecting at all.
If there is no SMTP response because the connection never starts, concentrate on name resolution, route selection, firewall egress, and the relay’s source-network restrictions. If a connection is established but the server closes it immediately, compare the selected port and TLS mode before changing credentials.
Authentication fails
Confirm the username, password, authentication mechanism, and allowed sender address. Check that the account is enabled for SMTP submission and that the relay permits this server’s source address. Do not respond to an authentication error by disabling TLS; password authentication should remain encrypted.
Check the credential file for accidental whitespace, wrong ownership, or permissions that prevent Exim from reading it. Keep the password private while collecting logs; SMTP responses and configuration diagnostics should not be copied with secrets included.
TLS negotiation fails
Compare the relay’s required encryption mode and port with Exim’s authentication and transport settings. Certificate or hostname validation errors can indicate a wrong relay name, an incomplete trust store, or a relay that expects a different TLS mode. The log’s SMTP status and TLS error are more useful than the queue state alone.
Using an IP address where the relay expects a certificate name can also produce a name-validation failure. Prefer the provider’s documented hostname and confirm that the system can validate the certificate chain supplied by the relay.
Messages remain deferred
Exim keeps deferred messages in its queue and records retry behavior in the main log. Fix the underlying network, DNS, authentication, sender-policy, or TLS problem first, then run sudo exim -qff when appropriate. If the relay continues to defer mail, use its returned SMTP status to determine whether the issue is temporary capacity, rate limiting, policy, or an invalid recipient.
Do not interpret a nonempty queue as proof that the configuration is wrong. Queueing is normal while Exim follows its retry schedule. The important evidence is the latest SMTP response and whether the relay eventually accepts the message. For a corrected transient failure, a forced queue run can provide a quick confirmation without waiting for the next retry interval.
The message is accepted locally but never arrives
Check the main log for a relay handoff, then check the recipient mailbox and any filtering or quarantine notices. If Exim handed the message to the smarthost, the remaining decision belongs to that service. Confirm that the envelope sender, header sender, recipient, and relay account all comply with the provider’s policy.
Best Value
- 【No Drill Mounted】Cable management tray can be assembled in as little as 3 minutes or less-simply. Side clips easily clampe the edge of desk, pass through the holes on the sides, and secure excess cables with baskets. Desk cable management supports inward or outward installation to meet your needs in different scenarios, and provides you with great convenience when collecting and organizing wires.
- 【Rubber Pad Protects Desk】Wire organizer under desk built-in soft rubber pads on the clamp protect your desk from scratches, so you will not damage your furniture or office.
- 【Sturdy and Beautiful】Cord management under desk is made of high-quality carbon steel and holds about 15 lbs. The wire basket has 2 holes on each side of the tray to enable your cables to pass freely. Cable baskets are suitable for desk thickness use from 0.4" to 2.4".
- 【Space Saving & Keep Organized】Desk cable management tray holds all your power cords, outlet strips, USB hubs and computer transformers hidden from your feet, and the data cables will not enter the vacuum cleaner to keep your desk clean and tidy. Desk wire organizer is also suitable for use in the kitchen and outdoors.
- 【Reduce Safety Risks】Cable tray under desk keeps all plugs away from your kids, no more worry about tripping. Using 2 holes wire tray saves extra space, helps you easily cabling and wire protection. The mesh design is not easy to accumulate dust, but avoids safety accidents caused by messy wires.
Operational checks after setup
- Keep the relay hostname, port, TLS requirement, and credential owner documented for future maintenance.
- Recheck the queue and main log after changing the relay or credentials.
- Confirm that applications are submitting through
/usr/sbin/sendmailor the local SMTP interface expected by their configuration, rather than bypassing Exim with an unrelated direct-delivery setting. - Monitor rejected and deferred messages so an expired password or relay policy change does not silently stop system alerts.
- Limit inbound firewall exposure; a send-only host does not need to advertise itself as a public receiving server merely because Exim is installed.
Review the configuration after Ubuntu or Exim package updates. If a package update changes a template or asks configuration questions again, confirm that the smarthost/no-local-mail choice, relay value, authentication arrangement, and TLS policy remain correct. Regenerate and restart after any source change.
Keep a small operational record of the relay contact, approved sender addresses, and the location and permissions of the credential file. This makes it easier to distinguish a local Exim problem from a provider-side account or policy change without exposing the password itself.
Do these 3 things before closing this tab:
1Repair Windows errors before they cause bigger problems2Scan for outdated or missing drivers - takes under a minute3Clear out junk files and repair common Windows errorsThe resulting design is deliberately simple: Ubuntu generates local mail, Exim queues it, and the configured smarthost performs authenticated or permitted onward delivery. When a message fails, the queue and SMTP response identify whether the fault is local configuration, network access, authentication, TLS, or the relay’s own policy.
Frequently Asked Questions
Which Exim option is correct for an outbound-only Ubuntu server?
Choose mail sent by smarthost; no local mail in dpkg-reconfigure exim4-config. Debian describes this as the client configuration for a system that is not responsible for a local email domain.
Can I use an IP address instead of a relay hostname?
The wizard accepts a hostname or IP address, but use the relay provider’s documented hostname when TLS certificate validation depends on that name. An IP can cause hostname or certificate validation failures.
How do I specify a non-standard SMTP port?
Append two colons and the port to the relay host, such as smtp.example.net::587. Use the exact port and encryption mode supplied by the relay operator.
Outdated Drivers Are Slowing You Down
One free scan finds every outdated or missing driver and matches the right update for your exact hardware.Free scan · exact hardware matchPC Slower Than It Used to Be?
A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11Do I always need an SMTP username and password?
No. A relay may authorize the server’s network without credentials. If it requires SMTP authentication, configure the documented mechanism and protect password authentication with TLS.
Why did my message stay in the Exim queue?
A queued message may be waiting for its normal retry time after a temporary failure. Read /var/log/exim4/mainlog for the SMTP response, correct the network, DNS, authentication, sender-policy, or TLS problem, and use sudo exim -qff to retry when appropriate.
What is the difference between update-exim4.conf and restarting Exim?
update-exim4.conf generates the active configuration from Debian’s stored answers and templates. systemctl restart exim4 makes the running service use that generated configuration. After source edits, perform both steps.
Should I edit the generated Exim configuration directly?
No. Edit the Debian-managed answers or split configuration sources, then run sudo update-exim4.conf. Direct edits to generated output can be overwritten during the next regeneration.
How can I verify that the host is really send-only?
Submit a test to an external recipient, confirm the main log shows handoff to the configured smarthost, and check that the host is not configured as the receiving server for external domains. Final receipt must also be confirmed at the destination.
What should I check when authentication works but mail is rejected?
Check the exact SMTP response, permitted sender address, recipient policy, account authorization, and the relay’s source-network rules. A valid login does not automatically authorize every sender or destination.
The Bottom Line
Install exim4, run sudo dpkg-reconfigure exim4-config, select mail sent by smarthost; no local mail, enter the relay and any required port, and configure authenticated TLS when required. Regenerate with sudo update-exim4.conf, restart Exim, then verify the queue, main log, relay handoff, and final receipt. Keep the relay policy and credentials protected, and troubleshoot from the exact SMTP response rather than guessing.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
The Tool Desk
Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →
