Troubleshooting Common SurgeMail Mail Server IssuesSurgeMail is a versatile, high-performance mail server used by ISPs, businesses, and hobbyists. Like any mail server, it can experience issues that affect delivery, security, or performance. This guide walks through common SurgeMail problems, how to diagnose them, and practical fixes—step by step.
1. Mail delivery failures (bounces, delayed or lost mail)
Symptoms: Users report undelivered messages, bouncebacks, or long delays.
Quick checks:
- Verify DNS (MX) records for the domain are correct and propagated.
- Ensure reverse DNS (PTR) matches the sending hostname — many receivers reject mismatches.
- Check disk space on the server; full disks can prevent mail queuing.
Diagnosis steps:
- Inspect SurgeMail logs (typically in the logs directory configured in SurgeMail). Look for SMTP transaction errors, 4xx/5xx responses, or repeated retries.
- Examine bounce messages to identify remote server response codes and reasons.
- Use command-line tests:
- telnet or openssl s_client to the remote SMTP server to reproduce transactions.
- dig MX domain and dig +short PTR ip to validate DNS.
Common causes and fixes:
- DNS misconfiguration — update MX/A/PTR records and wait for TTL propagation.
- Blacklisted IP — check IP against public RBLs; if listed, request delisting after fixing the cause (open relay, spam source).
- Misconfigured HELO/EHLO or hostname mismatch — set SurgeMail’s SMTP identity to a proper FQDN that matches PTR.
- Greylisting/temporary remote issues — verify logs for 4xx codes; allow retries or contact remote admin.
- Queue stuck due to permissions or corrupt queue files — stop SurgeMail, repair permissions (chown/chmod to surge user), clear or re-queue stuck messages safely, then restart.
2. Authentication failures (users can’t log in)
Symptoms: IMAP/POP/SMTP authentication failures, repeated login prompts, or “invalid credentials” errors.
Quick checks:
- Confirm user accounts exist and passwords are correct.
- Check authentication backend (local DB, PAM, LDAP, SQL) is reachable and responsive.
Diagnosis steps:
- Review SurgeMail auth logs for failures and error messages.
- Test authentication directly:
- For IMAP: use telnet/openssl s_client and attempt LOGIN or AUTH commands.
- For LDAP/SQL: use ldapsearch or run a test SQL query to ensure connectivity and binding credentials.
Common causes and fixes:
- Incorrect password hashing or encoding — ensure client and server use compatible encodings; reset password if needed.
- External auth server down — restart or fix LDAP/SQL server, check network/firewall rules.
- SSL/TLS misconfiguration blocking secure auth — verify certificates and cipher suites; check logs for SSL errors.
- Rate-limiting or account lockout — review SurgeMail’s throttle settings and unlock accounts if necessary.
3. TLS/SSL issues (certificate errors, TLS handshake failures)
Symptoms: Mail clients report certificate warnings, or connections fail when STARTTLS or SMTPS is attempted.
Quick checks:
- Verify certificate validity dates and that the certificate chain includes intermediate certificates.
- Confirm SurgeMail is configured to use the correct cert and private key files.
- Ensure the server’s hostname matches the certificate’s CN/SAN.
Diagnosis steps:
- Use openssl s_client -starttls smtp -crlf -connect host:25 (or port ⁄465) to inspect presented cert and handshake.
- Check SurgeMail logs for specific TLS errors: missing key, bad passphrase, or unsupported protocol.
Common causes and fixes:
- Expired or mismatched certificate — renew certificate and install full chain.
- Incorrect file permissions — private key must be readable by SurgeMail user only.
- Incomplete chain — include intermediate CA certs concatenated in the cert file.
- TLS protocol/cipher mismatch — update SurgeMail and OpenSSL or adjust allowed ciphers to match client expectations.
4. Spam and relay abuse (server used to send spam)
Symptoms: Complaints of spam sent from your domain, high outbound mail volume, blacklisting.
Quick checks:
- Verify SMTP relay policy — SurgeMail should not be an open relay.
- Check outbound queues and recent logs for unusual send rates or many different recipient addresses.
Diagnosis steps:
- Examine mail logs for patterns (same account sending many messages, or open relaying attempts).
- Check Postfix/SurgeMail relay settings — who is allowed to relay (authenticated users, trusted networks).
- Run an RBL check for your IP address.
Common causes and fixes:
- Compromised account — reset credentials, enable stronger passwords and rate limits.
- Open relay configuration — tighten relay restrictions to authenticated users only and specific IPs.
- Compromised web forms or scripts sending mail via SMTP — secure scripts, require authentication, or use an API with rate limits.
- Implement outbound throttling, connection limits, and monitoring; consider adding DKIM, SPF, and DMARC to reduce spoofing and improve reputation.
5. Performance issues (high CPU, memory, or slow mail delivery)
Symptoms: Server slow to accept connections, high load, delayed message processing.
Quick checks:
- Monitor system resources (top, vmstat) and I/O wait (iostat).
- Check number of concurrent SMTP/POP/IMAP connections in SurgeMail stats.
Diagnosis steps:
- Identify processes using most CPU/memory; correlate with SurgeMail worker processes.
- Review SurgeMail’s connection/concurrency settings and queue length.
- Evaluate disk performance and database backend responsiveness if using SQL/LDAP.
Common causes and fixes:
- Insufficient resources — increase CPU/RAM or scale horizontally (additional servers/load balancing).
- Too many simultaneous connections — lower max connections, enable connection throttling, or use a proxy/load balancer.
- Slow disk or I/O bottleneck — move queues to faster storage (SSD), optimize filesystem, or tune OS I/O scheduler.
- Memory leaks or outdated software — update SurgeMail and dependent libraries; restart service during maintenance windows.
6. Mail filtering and antivirus integration problems
Symptoms: Spam not filtered, false positives, or antivirus engine failing to scan attachments.
Quick checks:
- Ensure spam/anti-virus engines are running and reachable.
- Verify filter definitions/signatures are up to date.
Diagnosis steps:
- Check logs for errors from the spam or antivirus plugin (ClamAV, commercial engines).
- Test scanning by sending known test files (EICAR for antivirus, GTUBE for spam).
Common causes and fixes:
- Engine/service not running — restart ClamAV or other scanning services and enable automatic restarts.
- Signature updates blocked — allow outgoing connections to update servers or manually update definitions.
- Integration misconfiguration — confirm SurgeMail’s filter plugin paths and permissions.
7. Configuration errors after upgrades
Symptoms: Features stopped working, services fail to restart, or new errors appear after an upgrade.
Quick checks:
- Review SurgeMail release notes and migration guides for configuration changes.
- Compare previous configuration backups to the current configuration.
Diagnosis steps:
- Check logs for config parse errors or deprecated directives.
- Restore a backup of the working config to test if the issue is config-related.
Common causes and fixes:
- Deprecated settings — update configuration to new syntax as per release notes.
- File permission or ownership changes — correct permissions for config and data files.
- Missing modules or libraries — install required dependencies and restart.
8. Troubles with virtual domains and aliases
Symptoms: Mail for some domains not delivered, aliases not expanded, or user mailboxes missing.
Quick checks:
- Confirm virtual domain entries and mapping files are correct.
- Verify mailbox paths exist and permissions are correct.
Diagnosis steps:
- Use SurgeMail utilities to dump domain and alias mappings.
- Inspect log entries for “user not found” or domain lookup failures.
Common causes and fixes:
- Typos or missing entries in domain maps — correct and reload mappings.
- Mailboxes moved or permissions altered — restore or fix file paths and ownership.
- SQL/LDAP backend mapping errors — verify queries and schema mappings.
9. POP/IMAP sync and folder issues
Symptoms: Clients don’t see new mail, folder subscriptions fail, or messages disappear.
Quick checks:
- Verify IMAP/POP settings and namespace/prefix options for clients.
- Ensure quota limits aren’t blocking delivery.
Diagnosis steps:
- Inspect IMAP logs for errors when clients connect or sync folders.
- Use an IMAP diagnostic tool (e.g., imaptest) to enumerate folders and permissions.
Common causes and fixes:
- Namespace/prefix mismatch — configure client IMAP prefix (INBOX) correctly.
- Corrupted mailbox files — run mailbox repair tools or restore from backup.
- Quota exceeded — clear space or increase quota.
10. Backup and restore issues
Symptoms: Restores fail or backups incomplete.
Quick checks:
- Confirm backup schedules and targets (local, remote) are reachable and writable.
- Verify backup retention and rotation settings.
Diagnosis steps:
- Test backup and restore procedures on a non-production subset.
- Check backup logs for errors (permissions, network failures).
Common causes and fixes:
- Incomplete backups due to running processes locking files — use consistent snapshot tools (LVM snapshot, filesystem freeze) or stop SurgeMail briefly during backups.
- Permission errors — ensure backup user can read all mail and config files.
- Corrupted archives — switch archive format or verify checksum after backup.
Useful SurgeMail commands and log locations
- Start/stop/restart service: use your system init (systemctl restart surgemail) or the SurgeMail run scripts.
- Main log files: check the SurgeMail logs directory (path set in config; commonly under /var/surgemail/log or the installation dir).
- Queue directory: inspect mail queue path in SurgeMail config.
- Test SMTP: openssl s_client -starttls smtp -connect your.host:587
- DNS checks: dig MX yourdomain; dig -x your.ip.address
Preventive measures and best practices
- Keep SurgeMail and OS packages updated.
- Enforce strong authentication (complex passwords, consider 2FA where possible).
- Implement SPF, DKIM, and DMARC to protect domain reputation.
- Monitor logs and set alerts for unusual outbound volume or auth failures.
- Regularly backup configuration and maildirs; test restores.
- Use TLS with valid certificates and automate renewal (Let’s Encrypt or an ACME client, where supported).
If you want, I can: produce a checklist from this article, create sample SurgeMail config snippets for specific issues (TLS, relay restrictions, LDAP auth), or walk through diagnosing a specific log excerpt you paste here.
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