[{"data":1,"prerenderedAt":29},["ShallowReactive",2],{"doc-en-unblock-smtp-ports-vps":3},{"path":4,"slug":5,"title":6,"description":7,"category":8,"subcategory":9,"icon":10,"date":11,"author":12,"order":13,"image":14,"tags":15,"keywords":20,"docGroup":26,"docGroupIcon":26,"link_fr":27,"bodyHtml":28},"\u002Fdocs\u002Fen\u002Fvps\u002Fvps-linux\u002Funblock-smtp-ports-vps","unblock-smtp-ports-vps","How to unblock SMTP ports on your Winheberg VPS","SMTP ports are blocked by default on Winheberg VPSes. Learn why, how to check the block and how to request opening them for a legitimate use.","vps","vps-linux","tabler:file-text","2026-07-24","Winheberg",43,"\u002Fstatics\u002Fimages\u002Fdocs\u002Fen\u002Fvps-linux\u002Funblock-smtp-ports-vps.webp",[16,8,17,18,19],"smtp","mail","ports","security",[21,22,23,24,25],"smtp ports blocked vps","unblock smtp vps","port 25 blocked","send mail vps","smtp winheberg","","\u002Fdocs\u002Fvps-linux\u002Fdebloquer-ports-smtp-vps","\u003Ch2>Context\u003C\u002Fh2>\n\u003Cp>You have set up a service on your \u003Cstrong>Winheberg VPS\u003C\u002Fstrong> that needs to send emails, website notifications, monitoring alerts or a contact form, but the mails do not go out? Before hunting for a bug in your Postfix or Sendmail, know that it is probably normal, all SMTP ports are blocked by default on Winheberg VPSes.\u003C\u002Fp>\n\u003Cp>This guide explains why we block these ports, how to check that this is indeed the cause, and how to request them to be opened if you have a legitimate use.\u003C\u002Fp>\n\u003Cdiv class=\"markdown-alert markdown-alert-important\">\u003Cspan class=\"alert-icon\">\u003Csvg xmlns=\"http:\u002F\u002Fwww.w3.org\u002F2000\u002Fsvg\" width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\">\u003Cpath d=\"M12 22c5.523 0 10-4.477 10-10S17.523 2 12 2 2 6.477 2 12s4.477 10 10 10z\"\u002F>\u003Cpath d=\"M12 8v4\"\u002F>\u003Cpath d=\"M12 16h.01\"\u002F>\u003C\u002Fsvg>\u003C\u002Fspan>\u003Cdiv class=\"markdown-alert-body\">\u003Cp>Blocking outbound SMTP ports is common practice among many hosts and cloud providers worldwide. It is not an arbitrary limitation, it is a collective protection measure against mass spam and against the degradation of the host's IP range reputation.\u003C\u002Fp>\n\u003C\u002Fdiv>\u003C\u002Fdiv>\n\u003Ch2>Prerequisites\u003C\u002Fh2>\n\u003Cul>\n\u003Cli>A \u003Cstrong>Linux VPS\u003C\u002Fstrong> with Winheberg in service\u003C\u002Fli>\n\u003Cli>Root access over SSH to test outbound connections\u003C\u002Fli>\n\u003Cli>A Winheberg client account with truthful information and a valid email address\u003C\u002Fli>\n\u003C\u002Ful>\n\u003Ch2>Which ports are blocked?\u003C\u002Fh2>\n\u003Cp>Winheberg blocks by default the standard ports used by the SMTP protocol to send emails.\u003C\u002Fp>\n\u003Ctable>\n\u003Cthead>\n\u003Ctr>\n\u003Cth>Port\u003C\u002Fth>\n\u003Cth>Protocol\u003C\u002Fth>\n\u003Cth>Use\u003C\u002Fth>\n\u003C\u002Ftr>\n\u003C\u002Fthead>\n\u003Ctbody>\u003Ctr>\n\u003Ctd>\u003Cstrong>25\u003C\u002Fstrong>\u003C\u002Ftd>\n\u003Ctd>SMTP\u003C\u002Ftd>\n\u003Ctd>Relay between mail servers (server-to-server)\u003C\u002Ftd>\n\u003C\u002Ftr>\n\u003Ctr>\n\u003Ctd>\u003Cstrong>465\u003C\u002Fstrong>\u003C\u002Ftd>\n\u003Ctd>SMTPS\u003C\u002Ftd>\n\u003Ctd>SMTP with implicit TLS encryption\u003C\u002Ftd>\n\u003C\u002Ftr>\n\u003C\u002Ftbody>\u003C\u002Ftable>\n\u003Cp>The block only concerns outbound connections from your VPS toward other servers. You can still receive emails normally if you host an inbound mail server.\u003C\u002Fp>\n\u003Ch2>Why does Winheberg block these ports by default?\u003C\u002Fh2>\n\u003Cp>The SMTP protocol has historically been the main vector of spam on the Internet. Any compromised server can send millions of emails in a few hours, which raises several problems.\u003C\u002Fp>\n\u003Cul>\n\u003Cli>\u003Cstrong>Spam protection\u003C\u002Fstrong>, preventing a compromised VPS from being hijacked to send spam at scale\u003C\u002Fli>\n\u003Cli>\u003Cstrong>Reputation preservation\u003C\u002Fstrong> of Winheberg's IP ranges, because if our IPs were blacklisted by major mail providers like Gmail or Outlook, none of our clients could send emails\u003C\u002Fli>\n\u003Cli>\u003Cstrong>Compliance\u003C\u002Fstrong> with the modern hosting standards expected by network operators and anti-abuse services\u003C\u002Fli>\n\u003C\u002Ful>\n\u003Cp>So this block is in your interest as much as ours. If our IPs stay clean, your emails land in inboxes and not in spam folders.\u003C\u002Fp>\n\u003Ch2>How to check that this is really the cause?\u003C\u002Fh2>\n\u003Cp>Before requesting an opening, make sure the SMTP block is indeed the cause and not a problem in your mail configuration.\u003C\u002Fp>\n\u003Cp>Connect to your VPS over SSH and test the connections toward an external SMTP server, here Gmail.\u003C\u002Fp>\n\u003Cpre>\u003Ccode class=\"language-bash\">timeout 5 bash -c "<\u002Fdev\u002Ftcp\u002Fsmtp.gmail.com\u002F25" && echo "Port 25 open" || echo "Port 25 blocked"\ntimeout 5 bash -c "<\u002Fdev\u002Ftcp\u002Fsmtp.gmail.com\u002F465" && echo "Port 465 open" || echo "Port 465 blocked"\n\u003C\u002Fcode>\u003C\u002Fpre>\n\u003Cp>If the commands return \u003Ccode>blocked\u003C\u002Fcode> or hang for 5 seconds with no response, the SMTP ports are indeed blocked and that is the cause of your problem.\u003C\u002Fp>\n\u003Ch2>Requesting the SMTP ports to be opened\u003C\u002Fh2>\n\u003Cp>If you have a legitimate use that requires sending emails from your VPS, you can request it from our team through a ticket in your client area.\u003C\u002Fp>\n\u003Cdiv class=\"markdown-alert markdown-alert-important\">\u003Cspan class=\"alert-icon\">\u003Csvg xmlns=\"http:\u002F\u002Fwww.w3.org\u002F2000\u002Fsvg\" width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\">\u003Cpath d=\"M12 22c5.523 0 10-4.477 10-10S17.523 2 12 2 2 6.477 2 12s4.477 10 10 10z\"\u002F>\u003Cpath d=\"M12 8v4\"\u002F>\u003Cpath d=\"M12 16h.01\"\u002F>\u003C\u002Fsvg>\u003C\u002Fspan>\u003Cdiv class=\"markdown-alert-body\">\u003Cp>For a request to be reviewed, your Winheberg client account must hold truthful information and a valid email address, your sending domain must be established for some time, and the SPF and DMARC records must be valid on that domain. Our team then carries out anti-abuse checks before any opening.\u003C\u002Fp>\n\u003C\u002Fdiv>\u003C\u002Fdiv>\n\u003Cdiv class=\"markdown-alert markdown-alert-caution\">\u003Cspan class=\"alert-icon\">\u003Csvg xmlns=\"http:\u002F\u002Fwww.w3.org\u002F2000\u002Fsvg\" width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\">\u003Ccircle cx=\"12\" cy=\"12\" r=\"10\"\u002F>\u003Cline x1=\"12\" y1=\"8\" x2=\"12\" y2=\"12\"\u002F>\u003Cline x1=\"12\" y1=\"16\" x2=\"12.01\" y2=\"16\"\u002F>\u003C\u002Fsvg>\u003C\u002Fspan>\u003Cdiv class=\"markdown-alert-body\">\u003Cp>Opening the SMTP ports is tied to a specific VPS, not to your overall client account. If you have several VPSes with Winheberg and want to send emails from several of them, you will need to open one ticket per VPS concerned. Each request is reviewed independently.\u003C\u002Fp>\n\u003C\u002Fdiv>\u003C\u002Fdiv>\n\u003Cdiv class=\"markdown-alert markdown-alert-warning\">\u003Cspan class=\"alert-icon\">\u003Csvg xmlns=\"http:\u002F\u002Fwww.w3.org\u002F2000\u002Fsvg\" width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\">\u003Cpath d=\"M10.29 3.86L1.82 18a2 2 0 0 0 1.71 3h16.94a2 2 0 0 0 1.71-3L13.71 3.86a2 2 0 0 0-3.42 0z\"\u002F>\u003Cline x1=\"12\" y1=\"9\" x2=\"12\" y2=\"13\"\u002F>\u003Cline x1=\"12\" y1=\"17\" x2=\"12.01\" y2=\"17\"\u002F>\u003C\u002Fsvg>\u003C\u002Fspan>\u003Cdiv class=\"markdown-alert-body\">\u003Cp>The unblock is not permanent. Once opened, you are responsible for keeping a clean usage of your VPS. In case of abuse, our team may re-enable the SMTP block to protect the reputation of our IP ranges and the ecosystem of our clients.\u003C\u002Fp>\n\u003C\u002Fdiv>\u003C\u002Fdiv>\n\u003Ch3>1. Access the billing client area\u003C\u002Fh3>\n\u003Cp>Log in to \u003Ccode>https:\u002F\u002Fbilling.winheberg.com\u003C\u002Fcode> with your Winheberg credentials, then in the top menu hover over \u003Cstrong>Assistance\u003C\u002Fstrong> and click \u003Cstrong>Open a ticket\u003C\u002Fstrong>, or use the blue \u003Cstrong>Open a ticket\u003C\u002Fstrong> button at the top right.\u003C\u002Fp>\n\u003Cimg src=\"\u002Fuploads\u002Fdocs\u002F1780137111123_firefox_ouZWeeAEaq.webp\" alt=\"Assistance menu and Open a ticket button in the Winheberg client area\" width=\"800\" \u002F>\n\n\u003Ch3>2. Choose the Technical department\u003C\u002Fh3>\n\u003Cp>On the \u003Cstrong>Open a ticket\u003C\u002Fstrong> page, you see 4 available departments, Sales, Technical, Billing and Other. For an SMTP opening request, click \u003Cstrong>Open a ticket\u003C\u002Fstrong> in the \u003Cstrong>Technical\u003C\u002Fstrong> section.\u003C\u002Fp>\n\u003Cimg src=\"\u002Fuploads\u002Fdocs\u002F1780137121161_firefox_KiyyVsYNE8.webp\" alt=\"Selecting the Technical department among the available support departments in the Winheberg client area\" width=\"800\" \u002F>\n\n\u003Cdiv class=\"markdown-alert markdown-alert-note\">\u003Cspan class=\"alert-icon\">\u003Csvg xmlns=\"http:\u002F\u002Fwww.w3.org\u002F2000\u002Fsvg\" width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\">\u003Ccircle cx=\"12\" cy=\"12\" r=\"10\"\u002F>\u003Cline x1=\"12\" y1=\"16\" x2=\"12\" y2=\"12\"\u002F>\u003Cline x1=\"12\" y1=\"8\" x2=\"12.01\" y2=\"8\"\u002F>\u003C\u002Fsvg>\u003C\u002Fspan>\u003Cdiv class=\"markdown-alert-body\">\u003Cp>The Technical department is open 7 days a week, so your requests are handled quickly. Do not choose Billing or Sales for this kind of request, it may lengthen the delay.\u003C\u002Fp>\n\u003C\u002Fdiv>\u003C\u002Fdiv>\n\u003Ch3>3. Fill in the ticket form\u003C\u002Fh3>\n\u003Cp>Once in the form, make sure to select the VPS concerned in the \u003Cstrong>Produit lié\u003C\u002Fstrong> field, then give a clear subject and a detailed message.\u003C\u002Fp>\n\u003Cimg src=\"\u002Fuploads\u002Fdocs\u002F1780137157726_firefox_nmwsiksqRl.webp\" alt=\"Technical ticket form with the Produit lié field to select the VPS concerned\" width=\"800\" \u002F>\n\n\u003Cp>Here is the information to fill in your ticket.\u003C\u002Fp>\n\u003Ctable>\n\u003Cthead>\n\u003Ctr>\n\u003Cth>Field\u003C\u002Fth>\n\u003Cth>What to enter\u003C\u002Fth>\n\u003C\u002Ftr>\n\u003C\u002Fthead>\n\u003Ctbody>\u003Ctr>\n\u003Ctd>\u003Cstrong>Ticket Department\u003C\u002Fstrong>\u003C\u002Ftd>\n\u003Ctd>Technical\u003C\u002Ftd>\n\u003C\u002Ftr>\n\u003Ctr>\n\u003Ctd>\u003Cstrong>Produit lié\u003C\u002Fstrong>\u003C\u002Ftd>\n\u003Ctd>The exact VPS for which you request the opening\u003C\u002Ftd>\n\u003C\u002Ftr>\n\u003Ctr>\n\u003Ctd>\u003Cstrong>Priority\u003C\u002Fstrong>\u003C\u002Ftd>\n\u003Ctd>Medium, enough for this kind of request\u003C\u002Ftd>\n\u003C\u002Ftr>\n\u003Ctr>\n\u003Ctd>\u003Cstrong>Subject\u003C\u002Fstrong>\u003C\u002Ftd>\n\u003Ctd>SMTP ports opening request\u003C\u002Ftd>\n\u003C\u002Ftr>\n\u003Ctr>\n\u003Ctd>\u003Cstrong>Message\u003C\u002Fstrong>\u003C\u002Ftd>\n\u003Ctd>The details of your intended use, see below\u003C\u002Ftd>\n\u003C\u002Ftr>\n\u003C\u002Ftbody>\u003C\u002Ftable>\n\u003Ch3>4. Detail your request in the message\u003C\u002Fh3>\n\u003Cp>In the \u003Cstrong>Message\u003C\u002Fstrong> field, provide the following so our team can process your request.\u003C\u002Fp>\n\u003Cul>\n\u003Cli>\u003Cstrong>Intended use\u003C\u002Fstrong>, describe precisely why you need to send emails, application notifications, contact form or monitoring alerts\u003C\u002Fli>\n\u003Cli>\u003Cstrong>Estimated volume\u003C\u002Fstrong>, the number of emails per day or per month you plan to send\u003C\u002Fli>\n\u003Cli>\u003Cstrong>Sending domain\u003C\u002Fstrong>, the domain name the mails will be sent from\u003C\u002Fli>\n\u003Cli>\u003Cstrong>SPF and DMARC confirmation\u003C\u002Fstrong>, you must confirm that the SPF and DMARC records are correctly configured and valid on your domain before the request\u003C\u002Fli>\n\u003C\u002Ful>\n\u003Cdiv class=\"markdown-alert markdown-alert-tip\">\u003Cspan class=\"alert-icon\">\u003Csvg xmlns=\"http:\u002F\u002Fwww.w3.org\u002F2000\u002Fsvg\" width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\">\u003Ccircle cx=\"12\" cy=\"12\" r=\"10\"\u002F>\u003Cpath d=\"M12 16v-4\"\u002F>\u003Cpath d=\"M12 8h.01\"\u002F>\u003C\u002Fsvg>\u003C\u002Fspan>\u003Cdiv class=\"markdown-alert-body\">\u003Cp>You can check the validity of your SPF and DMARC records with online tools like MXToolbox or Mail-Tester before opening the ticket. A complete file from the start speeds up processing.\u003C\u002Fp>\n\u003C\u002Fdiv>\u003C\u002Fdiv>\n\u003Ch3>5. Review by our team\u003C\u002Fh3>\n\u003Cp>Our team will review your request to make sure it is a legitimate use. This check is usually quick, but can take from a few hours to a few days depending on the ticket volume.\u003C\u002Fp>\n\u003Cdiv class=\"markdown-alert markdown-alert-important\">\u003Cspan class=\"alert-icon\">\u003Csvg xmlns=\"http:\u002F\u002Fwww.w3.org\u002F2000\u002Fsvg\" width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\">\u003Cpath d=\"M12 22c5.523 0 10-4.477 10-10S17.523 2 12 2 2 6.477 2 12s4.477 10 10 10z\"\u002F>\u003Cpath d=\"M12 8v4\"\u002F>\u003Cpath d=\"M12 16h.01\"\u002F>\u003C\u002Fsvg>\u003C\u002Fspan>\u003Cdiv class=\"markdown-alert-body\">\u003Cp>The more detailed and professional your request, the more likely it is to be accepted quickly. A vague ticket like "please open SMTP" will require additional information and lengthen the delay.\u003C\u002Fp>\n\u003C\u002Fdiv>\u003C\u002Fdiv>\n\u003Ch2>Troubleshooting\u003C\u002Fh2>\n\u003Ch3>❌ My ticket was refused, what should I do?\u003C\u002Fh3>\n\u003Cp>A request may be set aside if the use is not clear enough, if the sending domain is not correctly configured, or if the client account holds incomplete information. Start by updating your client profile in the billing area with current information, check your SPF and DMARC DNS configuration, then open a new ticket detailing the following points.\u003C\u002Fp>\n\u003Cul>\n\u003Cli>The \u003Cstrong>exact service\u003C\u002Fstrong> you use, Postfix, Sendmail or a custom application\u003C\u002Fli>\n\u003Cli>The \u003Cstrong>type of emails\u003C\u002Fstrong> you send, transactional, notifications or newsletter\u003C\u002Fli>\n\u003Cli>The precise \u003Cstrong>volume\u003C\u002Fstrong> planned\u003C\u002Fli>\n\u003Cli>Your \u003Cstrong>domain\u003C\u002Fstrong> and confirmation that SPF and DMARC are valid\u003C\u002Fli>\n\u003Cli>The \u003Cstrong>VPS concerned\u003C\u002Fstrong> selected in Produit lié\u003C\u002Fli>\n\u003C\u002Ful>\n\u003Ch3>❌ I want to send many emails per day, will it go through?\u003C\u002Fh3>\n\u003Cp>For large volumes, more than a few hundred emails per day, our team will review your request with particular attention. You will need to justify the use, specify the type of emails, transactional, marketing or notifications, and demonstrate that your mail infrastructure SPF, DKIM and DMARC is correctly configured.\u003C\u002Fp>\n\u003Ch3>❌ The ports are open but my mails end up in spam\u003C\u002Fh3>\n\u003Cp>Opening the ports is not enough for good deliverability. You also need to set up the following records.\u003C\u002Fp>\n\u003Cul>\n\u003Cli>An \u003Cstrong>SPF\u003C\u002Fstrong> record on your domain\u003C\u002Fli>\n\u003Cli>A \u003Cstrong>DKIM\u003C\u002Fstrong> signature to authenticate your emails\u003C\u002Fli>\n\u003Cli>A \u003Cstrong>DMARC\u003C\u002Fstrong> policy to indicate how to handle unauthenticated mails\u003C\u002Fli>\n\u003C\u002Ful>\n\u003Cp>Without these records, Gmail and Outlook will treat your mails as suspicious and send them to spam or reject them.\u003C\u002Fp>\n\u003Ch3>❌ I unblocked SMTP on one VPS but not on my other VPS\u003C\u002Fh3>\n\u003Cp>This is normal. Opening the SMTP ports is tied to a specific VPS, not to your overall account. If you want to send emails from another VPS, you need to open a new ticket for that VPS by selecting the right \u003Cstrong>Produit lié\u003C\u002Fstrong> in the form. Each request is reviewed independently, but if you already had a legitimate unblock on a first VPS, the second is generally handled faster.\u003C\u002Fp>\n\u003Ch3>❌ SMTP was unblocked then re-blocked\u003C\u002Fh3>\n\u003Cp>If your emails were going out correctly and suddenly stop, the block was probably re-enabled on your VPS. The unblock is not permanent, it can be removed in case of observed abuse, in order to protect the reputation of our IP ranges and the ecosystem of our clients. If you believe the re-enabling is a mistake, open a new ticket detailing the situation, backed by your mail server logs and your recent configuration.\u003C\u002Fp>\n\u003Ch3>❌ How long to get a reply to my ticket?\u003C\u002Fh3>\n\u003Cp>Generally, our team handles SMTP opening requests within a few hours to 48 hours depending on the volume. The more complete your ticket from the start, the faster it is processed, with no back and forth to ask for details.\u003C\u002Fp>\n\u003Ch2>Best practices\u003C\u002Fh2>\n\u003Cul>\n\u003Cli>\u003Cstrong>Configure SPF, DKIM and DMARC\u003C\u002Fstrong> on your domain even before requesting the SMTP ports to be opened\u003C\u002Fli>\n\u003Cli>\u003Cstrong>Monitor blacklists\u003C\u002Fstrong> with a tool like MXToolbox to check that your IP is not listed\u003C\u002Fli>\n\u003Cli>\u003Cstrong>Limit the sending volume\u003C\u002Fstrong> to what you actually need\u003C\u002Fli>\n\u003Cli>\u003Cstrong>Secure your applications\u003C\u002Fstrong>, contact forms and sending scripts to prevent an attacker from using your server to spam\u003C\u002Fli>\n\u003Cli>\u003Cstrong>Document your mail infrastructure\u003C\u002Fstrong> so you can troubleshoot quickly if something goes wrong\u003C\u002Fli>\n\u003C\u002Ful>\n\u003Ch2>Need help?\u003C\u002Fh2>\n\u003Cp>If you are unsure whether you need to open the SMTP ports, or about your mail server configuration, our team is available. Open a ticket in the \u003Cstrong>Technical\u003C\u002Fstrong> department from your client area, fill the \u003Cstrong>Produit lié\u003C\u002Fstrong> field with the VPS concerned, and we will point you to the solution best suited to your need.\u003C\u002Fp>\n\u003Cp>Your VPS is now ready to send emails in the best conditions 📧\u003C\u002Fp>\n",1788993144416]