I was trying to send a mail through Java the other day and kept stumbling upon the following exception:<\/p>\n
javax.mail.MessagingException: 501 HELO requires valid address<\/p><\/blockquote>\n
I thought it was caused by an authentication problem or my provider preventing me from sending from a random address.
\nThe former I tried to address by making sure I was fully authenticated as to prove I was not trying to send spam. In java mail the following properties are relevant for sending authenticated mail using TLS:<\/p>\n-Dmail.smtp.host=<your smtp server>
\n-Dmail.smtp.port=587
\n-Dmail.smtp.username=<your username>
\n-Dmail.smtp.password=<your password>
\n-Dmail.smtp.auth=true
\n-Dmail.smtp.starttls.enable=true<\/p><\/blockquote>\nand setting an authenticator on the mail session object:<\/p>\n
Session session = Session.getDefaultInstance(System.getProperties(), new javax.mail.Authenticator() {
\nprotected PasswordAuthentication getPasswordAuthentication() {
\nreturn new PasswordAuthentication(MAIL_USER, MAIL_PWD);
\n}
\n});<\/p><\/blockquote>\nThe latter I tried to address by sending from an alias that was associated with the original mailbox (user\/pwd combo). Yet I kept getting the same exception.<\/p>\n
Looking up the SMTP protocol and testing with telnet, I found out that normally you are supposed to provide a domain name when issueing the EHLO or HELO command. Since the api does not provide any methods for that, I looked for some more properties and indeed, it turns out you need to set<\/p>\n
-Dmail.smtp.localhost<\/p><\/blockquote>\n
to make it provide the hostname for the EHLO command. According to the docs:
\n“Should not normally need to be set if your JDK and your name service are configured properly.<\/em>” but apparently my case was not normal \ud83d\ude42<\/p>\nAlso worth noting is that you can turn on debug output with:<\/p>\n
session.setDebug(true);<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"
I was trying to send a mail through Java the other day and kept stumbling upon the following exception: javax.mail.MessagingException: 501 HELO requires valid address I thought it was caused by an authentication problem or my provider preventing me from sending from a random address. The former I tried to address by making sure I … Continue reading Java mail and SMTP: “501 HELO requires valid address”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-627","post","type-post","status-publish","format-standard","hentry","category-programming"],"_links":{"self":[{"href":"https:\/\/mattiesworld.gotdns.org\/weblog\/wp-json\/wp\/v2\/posts\/627","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mattiesworld.gotdns.org\/weblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mattiesworld.gotdns.org\/weblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mattiesworld.gotdns.org\/weblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mattiesworld.gotdns.org\/weblog\/wp-json\/wp\/v2\/comments?post=627"}],"version-history":[{"count":3,"href":"https:\/\/mattiesworld.gotdns.org\/weblog\/wp-json\/wp\/v2\/posts\/627\/revisions"}],"predecessor-version":[{"id":630,"href":"https:\/\/mattiesworld.gotdns.org\/weblog\/wp-json\/wp\/v2\/posts\/627\/revisions\/630"}],"wp:attachment":[{"href":"https:\/\/mattiesworld.gotdns.org\/weblog\/wp-json\/wp\/v2\/media?parent=627"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mattiesworld.gotdns.org\/weblog\/wp-json\/wp\/v2\/categories?post=627"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mattiesworld.gotdns.org\/weblog\/wp-json\/wp\/v2\/tags?post=627"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}