What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Postfix has no documented universal ceiling of two emails per minute. That pattern is a diagnostic clue: either an SMTP client is being limited by a nonzero per-client setting, the anvil service is counting events in a 60-second window, or messages are accepted and then delayed in the queue or by remote servers. Start by proving where the time is spent before changing a limit.
Need a server to try this on? Antihost offers Linux VPS plans with NVMe storage, full root access and a 14-day free trial.
Check the effective configuration for the service that receives the mail, match timestamps with the mail log, and inspect queue IDs. Only after a log entry shows an SMTP request being rejected or deferred should you change an smtpd rate parameter. A successful 250 acceptance is a different problem from slow remote delivery.
As an Amazon Associate I earn from qualifying purchases.
Recommended Free Tools
What a two-emails-per-minute pattern actually means
The number two is not a Postfix default. The Postfix postconf(5) reference defines several independent client controls, including message-delivery requests, connection attempts, simultaneous connections, recipients, new TLS sessions and, in newer releases, AUTH commands. Their effective values can be set globally in main.cf or overridden for one listener in master.cf.
Postfix documents smtpd_client_message_rate_limit as the maximum number of message-delivery requests a client may make during the interval defined by anvil_rate_time_unit. Its documented default is 0, meaning unlimited. The documented default for anvil_rate_time_unit is 60 seconds, so a locally configured count can look exactly like a per-minute allowance. A two-per-minute symptom therefore points to local configuration or another bottleneck, not to a universal Postfix cap.
#1 Best Overall
- [Ultra-Lightweight Ear Buds Designed for Small Ears] Each earbud weighs only 3.7g and features a compact, ergonomic in-ear design made especially for small ears. Secure, low-profile, and comfortable for workouts, all-day wear or overnight sleeping.The ultra-slim profile sits flush in your ear with no hard edges poking or rubbing, so you can even sleep on your side without discomfort.
- [Immersive Stereo Sound with TOZO OrigX Technology] TOZO OrigX tuning delivers clear vocals, balanced mids, and natural stereo sound for music, podcasts, and videos.
- [Long Battery Life for Daily Use] Get up to 7 hours of playtime on a single charge, with up to 32 hours total using the charging case—ideal for workdays, commuting, and extended listening sessions.
- [Bluetooth 5.3 & Stable Connection] Bluetooth 5.3 provides fast pairing, stable wireless performance, and reduced dropouts as you move around home or office.
- [Deep Bass with Clear Vocals] High-performance drivers produce punchy bass while keeping vocals clean and detailed for everyday listening.
| Where the delay appears | Evidence to collect | Likely branch |
|---|---|---|
| During SMTP submission | Reject, defer, or disconnect at CONNECT, AUTH, MAIL, RCPT, or message submission; timestamps repeat at a fixed interval | Client rate, connection, recipient, TLS, AUTH, or anvil accounting |
| Immediately after acceptance | SMTP client receives 250, but queue IDs remain queued or deferred |
Queue scheduling, DNS, TLS negotiation, transport concurrency, or remote 4xx responses |
| Only one IP or account | Other senders proceed normally; log entries identify one address or username | Per-client limit, authentication policy, or application behavior |
| Every sender | All clients show similar queue age or remote responses | Global transport, destination, DNS, or provider problem |
| Variable pauses | Delays change with destination and remote response codes | Remote throttling or retry/backoff rather than a fixed anvil window |
Use the fixed-window, scope, and log evidence together. A queue that grows without any SMTP rejection is not proof that an smtpd limit is active.
First diagnostic pass: capture facts before changing Postfix
- Record the version and effective settings. Run
postconf mail_versionandpostconf -n. The first command identifies the installed Postfix version; the second prints non-defaultmain.cfsettings. Save the output so you can compare it after a change. - Inspect the receiving service. Run
postconf -M submission/inet, replacingsubmission/inetwith the service that actually receives the traffic, such assmtp/inetor another custom listener. A submission service can have settings different from the global values. - Read every relevant client control. Query the effective values with
postconf smtpd_client_message_rate_limit smtpd_client_connection_rate_limit smtpd_client_connection_count_limit smtpd_client_recipient_rate_limit smtpd_client_new_tls_session_rate_limit smtpd_client_auth_rate_limit smtpd_client_event_limit_exceptions anvil_rate_time_unit. If your installed version does not recognizesmtpd_client_auth_rate_limit, omit it; that parameter exists only in newer versions. - Search the mail log by identity and time. Search for the sender’s IP address, authenticated username, queue ID, the words
rejectanddefer,anvil, and the service name. On systems using a traditional log file, this may be/var/log/maillogor/var/log/mail.log; use your distribution’s actual file. Correlate the apparent two-per-minute timestamps with the SMTP command at which Postfix acted. - Compare configuration layers. Review
main.cfand the service stanza inmaster.cf. A service-specific-osetting onsubmission,smtps, or another listener overrides the global value for that service. Looking only atmain.cfcan therefore produce the wrong answer. - Check queue state. Run
postqueue -p. Note the number of queued messages, their oldest age, destination domains, and whether entries are active or deferred. For representative queue IDs, locate the corresponding log lines and record remote response text.
Do not edit a value simply because it sounds related. The log should identify whether Postfix is limiting a message request, connection, recipient, TLS session, or AUTH command. If it does not, stay on the queue and delivery branch until the evidence changes.
The Tool Desk
Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Which Postfix settings can create the symptom?
The following controls are independent. A low value in one does not imply that the others are low. Values shown as “0” are the documented defaults where the Postfix reference explicitly states that default; for controls whose default varies by version or is not established here, inspect the installed documentation and effective output.
| Parameter | What it counts | Documented default or qualification | Typical log location |
|---|---|---|---|
smtpd_client_message_rate_limit |
Message-delivery requests from one client during the anvil time unit | 0 (no limit) |
Message submission or MAIL transaction is rejected/deferred |
smtpd_client_connection_rate_limit |
New connections from one client during the time unit | 0 (no limit) |
Connection attempts are refused or deferred |
smtpd_client_connection_count_limit |
Simultaneous connections from one client | Inspect the installed version’s effective value | Excess parallel sessions are refused |
smtpd_client_recipient_rate_limit |
Recipients accepted from one client during the time unit | 0 (no limit) |
RCPT TO is rejected or deferred after a count |
smtpd_client_new_tls_session_rate_limit |
New TLS sessions from one client during the time unit | Inspect the installed version’s effective value | TLS handshakes or new secure sessions are limited |
smtpd_client_auth_rate_limit |
AUTH commands from one client; available in newer versions | Check whether the installed version supports it | Repeated authentication attempts are limited |
smtpd_client_event_limit_exceptions |
Clients exempt from the anvil event limits | Documented default is $mynetworks |
Trusted and untrusted clients behave differently |
anvil_rate_time_unit |
Length of the counting window used by rate controls | 60 seconds by default | Fixed, clock-like cadence in the logs |
The anvil service maintains the counters used by these controls. On low-traffic systems, the Postfix tuning guidance notes that anvil processes pick up main.cf changes as they run; a postfix reload can speed adoption on other systems. Counters and configuration reloads are separate concerns: reloading does not turn a limited value into an unlimited one.
How to fix an inbound SMTP or client rate limit
Make the smallest change that addresses the event named in the log. The Postfix documentation states: The purpose of this feature is to limit abuse. It must not be used to regulate legitimate mail traffic.
See the official parameter reference for syntax and version-specific behavior.
Rank #2
- 【IP68 Waterproof Multifunctinal Smart Watch】Torjalph fitness activity tracker smart watch is IP68 waterproof technology ,you can wear it when swimming,handwashing,it's rain-proof which means that you perform multiple exercise modes outside without worrying about sweat or rain corroding your fitness smart watch,and this watch equipped with a 230 mAh large capacity battery magnetic charging ,and this sports activity tracker watch can be used 5-7 days If fully charged.
- 【Larger 1.83'' Full Screen Watch & Multi-dial Selection】1.83 inch full HD color touch screen smart watch for men / women provides excellent 240*284 resolution image quality ,This Bluetooth smart watch offers a better touch experience and remarkable immersion and ,more than 200 watch faces for you to choose from App"Da Fit ", you can change the dial style according to your mood to wear keeping the world on your wrist
- 【Accurate Activity Tracker Smart Watch 】sports watch activity tracker uses sweat and dust resistant breathable silicone strap, our Fitness Tracker Smart Watch for Android iOS Phones supports 12 sports modes,walking,running,bicycle,swimming,badminton,basketball,football,rope skipping. This bluetooth calls smart watch for men women is lightweight and stylish, bringing more convenient and relaxing sports experience while also providing more protection.
- 【Your 24 Hour Personal Daily Health Monitor】Fitness watch for women men full touch screen IP67 waterproof bluetooth smartwatch for Android iOS Phones with heart rate blood pressure monitor multifunction Andriod smart watch with steps counter sleep monitor sports fitness watch, monitoring blood oxygen saturation allows you to understand your physical condition in real time to track fitness progress ,to know your health status in time.
- 【More Functions Bluetooth Call Smart Watch】This fitness activity smart watch full screen for iPhone and Android phones includes a bunch of new features including:The bluetooth smart watch can hang up the phone, receive and display WhatsAPP /Text /Facebook /Twitter /Messenger reminder.Support sedentary reminder, alarm clock, stopwatch, timer,weather information,music control, remote camera control compatible with Android 5.0 and above or iOS 9.0 and above smartphones.
1. Confirm the exact nonzero control
Suppose the log shows that the same client is deferred after two message submissions, and the effective output reports a nonzero smtpd_client_message_rate_limit. That is sufficient evidence to change the message-request limit. It is not evidence to raise the connection, recipient, TLS, and AUTH limits as well. If the rejection occurs at RCPT TO, investigate smtpd_client_recipient_rate_limit; if it occurs on connection creation, investigate the connection controls.
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 errors2. Decide whether the sender should be limited or exempt
For a legitimate, controlled submission client, first review smtpd_client_event_limit_exceptions and the actual mynetworks definition. The documented default exception list is $mynetworks. Verify that the sender’s address is really inside that narrowly defined trust boundary. Do not add an entire corporate, hosting, or internet range merely to make a test pass: an exception bypasses abuse controls for every host in that range.
3. Set only the implicated value
If a limit is not needed for a particular trusted service, set that particular parameter to 0 only after checking the installed-version documentation. For example, an administrator might use postconf -e 'smtpd_client_message_rate_limit = 0' to remove a global message-request limit, but that command is appropriate only when the global service is the one being tested and abuse protection is handled elsewhere. A service override in master.cf must be changed in that service’s stanza instead.
If a finite limit is desirable, choose a value and window that match the sender’s legitimate workload, then document the client scope. A two-per-minute pattern can be produced by a value of two with the default 60-second window, but the actual configured number and window must come from postconf, not from the symptom alone.
4. Validate syntax and reload
- Run
postfix checkto detect configuration and permission problems. - Run
postconf smtpd_client_message_rate_limit(or the parameter you changed) and confirm the effective value. - Run
postfix reloadso active Postfix services reread their configuration. - Repeat the same controlled submission from the same client and preserve the timestamps and queue IDs.
If the old behavior remains, verify that the test is reaching the listener you changed and that a master.cf -o override is not still enforcing another value.
Rank #3
- [Low Noise High Fidelity] New bee guitar cord with 22AWG oxygen-free-copper center conductors provides enhanced signal transfer, the PVC insulation material and the high-density stranded copper double shield provide noise rejection for quiet operation
- [Ideal for Choice] New bee 1/4 straight and right angle metal connectors, ensures a secure connection in any instrument, pedal, or amp jack. L shape great fro on stage guitar stands
- [Wide Compatible] Suitable for mixer, power amplifier, microphone, effector, decoder, equalizer, electoronic organ, electric guitar, electric bass and other electronic equipments. Widely used in the installation of smart home, karaoke speaker, professional stage audio, etc
- [Easy Disassemble] Making incidental repairs quick and easy! Very nice, flexible cable
- [Dont Hesite to Order] 24 hours customer services and professional technology team are standing by
Why a master.cf override can defeat a main.cf change
Postfix reads global defaults from main.cf, but each service in master.cf can supply -o parameter=value overrides. A provider commonly runs authenticated clients on submission or smtps, while local or relay traffic uses another service. If you change smtpd_client_message_rate_limit globally and the submission service has its own override, authenticated traffic will continue to see the service value.
Use postconf -M to list service definitions, open the matching master.cf stanza, and look for -o smtpd_client_... lines. Preserve unrelated options such as TLS and authentication settings. After editing, run postfix check, reload, and query the service again. Test through the same hostname, port, encryption mode, and credentials used by the application; testing port 25 does not validate a change made for port 587.
When messages are accepted but delivery is slow
An SMTP acceptance means Postfix accepted responsibility for the message; it does not mean the recipient server has accepted it. If the client receives 250, receives a queue ID, and disconnects normally, stop changing smtpd rate limits and follow the queue.
Inspect queue age and status
Run postqueue -p repeatedly during the test. A steadily increasing oldest age, many deferred entries, or concentration at one destination domain points to delivery rather than submission. Open the log entries for representative queue IDs and record whether the remote server returned a 4xx temporary failure, a 5xx permanent failure, a TLS error, a DNS error, or a connection timeout.
Check destination and transport constraints
- Remote 4xx replies: The receiving provider may be applying its own rate policy. Postfix will retry according to its queue and backoff behavior; the cadence can vary rather than repeating exactly every 60 seconds.
- DNS: Missing, slow, or inconsistent MX and A/AAAA resolution can delay each delivery attempt.
- TLS: Certificate validation, protocol negotiation, or a remote server that stalls during handshake can consume the apparent sending interval.
- Concurrency: Transport-specific concurrency and destination limits can serialize deliveries even when smtpd accepts new messages quickly.
- Retry timing: A queue that is deferred is governed by retry scheduling, not by the inbound client’s message-rate parameter.
Do not label any of these conditions “anvil throttling” without a log entry showing that an SMTP client event was limited. The observable symptom alone cannot distinguish the branches.
Rank #4
- Digital Family Calendar: BSIMB digital calendar wall touch screen puts an end to your chaotic life. Designed for busy families, the digital calendar keeps you organised and in step with your family. Assign different colours and tasks to each family member to make family scheduling easier and more intuitive.
- Easy Setup and Auto-Sync: Plug in, connect to WLAN and auto-syn your electric calendar in minutes. Digital wall calendar compatible with Google calendar, iCloud calendar, Outlook calendar, Cozi calendar and Yahoo calendar. Add events directly on the device or through the ecalendar app. Electronic calendar stays current whether you're at work or traveling—no manual updates needed.
- All-In-One Home Assistant: Smart calendar builds habits and encourage independence with personalised chores. Display daily meal plan to reduce the daily ‘What's for dinner?’ stress. To-do lists keep track of everything you want. Turning chores into valuable achievements with stars and rewards, making life easier and more enjoyable.
- Manage Anytime Anywhere: BSIMB electronic calendar for family stay connected with the powerful ecalendar app. Access and manage your digital wall calendar anytime, anywhere with free features like stars & rewards, photo screensaver, chore charts, meals plans, to-do lists etc. Electronic planner paid features like Magic Import tailor advanced tools for users with special needs.
- Stay in Touch with Loved Ones: Share photos or videos from your phone to electronic wall calendar with app, instantly update your life moment, and keep in touch with your family, especially those who are far away; you can also surprise your smart calendar digital wall by sending him a wish card; it's also great for keeping tech-illiterate elders in touch with the youngsters.
Application behavior can mimic a Postfix limit
An application that opens a new SMTP connection for every small message may spend most of its time on TCP setup, TLS negotiation, and authentication. If it submits one message, waits, closes the connection, and repeats, the resulting cadence can look like a server limit even when every request is accepted immediately.
Where message privacy and recipient semantics allow, submit multiple recipients in one message and reuse an authenticated SMTP connection for a batch. The Postfix tuning guidance recommends submitting multiple recipients per message when appropriate and using SMTP submission rather than invoking /usr/sbin/sendmail for application traffic. These changes reduce client-side overhead; they do not bypass a legitimate server-side abuse limit.
Measure this branch by logging the application’s connect, TLS, AUTH, MAIL, RCPT, DATA, and response timestamps. Compare one-message-per-connection with a controlled persistent-connection test. If the server log shows immediate acceptance for both tests while the application reports a delay, fix connection management or its own worker/concurrency settings.
Compare the competing causes before choosing a fix
| Diagnostic axis | Inbound rate limit | Queue or remote delivery delay | Application connection overhead |
|---|---|---|---|
| Delay location | Before or during SMTP acceptance | After a queue ID and acceptance response | Mostly before each SMTP transaction |
| Scope | One client IP/account or a defined exception set | One destination, many destinations, or all outbound traffic | Usually one application process or worker pool |
| Cadence | Fixed count in the configured anvil window | Variable according to remote replies and retry schedule | Repeats with connection, TLS, and AUTH costs |
| Strong evidence | Explicit reject/defer text naming a client event or anvil | Queue age, deferred status, and remote response text | Client timing shows a new connection for every message |
| Configuration layer | main.cf value or master.cf service override |
Transport, DNS, TLS, concurrency, and retry settings | Application SMTP pooling, batching, and worker settings |
This comparison prevents a common mistake: removing abuse protection because a remote recipient is slow, or tuning remote-delivery concurrency when the submission listener is rejecting the client.
Safe change-and-verify procedure
- Capture a baseline. Save
postconf mail_version, the relevant effective parameters,postqueue -poutput, queue age, and a short log excerpt. Time a controlled test with a known sender and a small, repeatable message set. - Change one thing. Edit only the parameter implicated by the log. Keep the sender scope, numeric value, and time window explicit. Do not simultaneously alter recipient limits, connection limits, transport concurrency, and retry timers.
- Validate and reload. Run
postfix check, verify the effective value withpostconf, and runpostfix reload. Confirm that the receiving service is the one you changed. - Repeat the same test. Use the same client, port, authentication mode, message count, and destinations. Compare acceptance timestamps, queue age, and remote-delivery responses with the baseline.
- Review security impact. If the change increases capacity for untrusted clients, restore a protective limit and design a narrowly scoped exception for known submission clients instead. Record who owns that exception and why it exists.
- Monitor after the change. Watch rejected connections, AUTH failures, queue growth, and destination responses over a representative busy period. A successful five-message test does not prove that abuse controls are still adequate.
Common failure modes and recovery steps
The value says zero, but the client still gets two messages per minute
Check for a service-specific master.cf override, a different listener than the one tested, or a limit enforced by a front-end proxy or submission application. Confirm the actual service with postconf -M and match the log’s port and process name. Then inspect queue and remote responses before making another smtpd change.
The exception appears correct, but the sender is still limited
Verify the source address Postfix sees, especially when NAT, a load balancer, or an IPv6 path is involved. Confirm that the address is included in the evaluated mynetworks value and that the exception list was reloaded. Avoid solving an address mismatch by adding a broad network range.
Reload reports success, but behavior is unchanged
Run postfix check, query the effective parameter, and inspect the log for the process handling the connection. A stale service process, a second Postfix instance, or an unedited service override can make a correct-looking global value irrelevant. On low-traffic systems, anvil counters may persist until its processes cycle; a reload usually accelerates configuration adoption, but it does not erase evidence from the previous window.
Quick wins for a faster PC:
Clear out junk files and repair common Windows errorsFree Scan →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Repair Windows errors before they cause bigger problemsFix Now →The queue is empty, yet the application reports a two-per-minute rate
Instrument the application and SMTP client. Record connection reuse, TLS handshakes, AUTH calls, server responses, and pauses between messages. An empty queue with successful acceptances points away from remote delivery and toward application pacing or a client-side worker limit.
Security boundaries when removing a limit
Per-client limits exist to contain abuse, credential attacks, connection floods, and runaway applications. Removing a limit globally can let a compromised account or open relay attempt consume CPU, disk, network, and downstream reputation. Prefer authenticated submission on a dedicated service, a narrowly scoped trusted-client exception, and a finite limit for everyone else.
Keep mynetworks as small as operationally possible. Review IPv4, IPv6, container, VPN, and proxy source addresses separately. If a vendor or internal application needs higher throughput, identify its stable source address or authenticated identity and exempt only that identity where the installed Postfix version supports it. Recheck logs after deployment so the exception does not silently cover unrelated clients.
Bottom line
Fixing “two emails per minute” starts with classification, not a blanket limit increase. Postfix’s documented message, connection, and recipient rate-limit defaults are unlimited, while the anvil counting window defaults to 60 seconds. Prove whether a specific smtpd control is rejecting the client, whether a service override is active, or whether accepted messages are waiting on the queue and remote servers. Then make one narrowly scoped change, validate it, reload Postfix, and repeat the same measured test.
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.
