{"id":1449,"date":"2014-09-12T09:10:49","date_gmt":"2014-09-12T09:10:49","guid":{"rendered":"http:\/\/andyparkes.co.uk\/blog\/?p=1449"},"modified":"2014-09-12T09:19:10","modified_gmt":"2014-09-12T09:19:10","slug":"syntactically-invalid-helo-arguments","status":"publish","type":"post","link":"https:\/\/andyparkes.co.uk\/blog\/index.php\/2014\/09\/12\/syntactically-invalid-helo-arguments\/","title":{"rendered":"Syntactically invalid HELO argument(s)"},"content":{"rendered":"

Yesterday I had a client report that certain emails were being bounced<\/p>\n

The SMTP error message was this<\/p>\n

\n

501 Syntactically invalid HELO argument(s)<\/strong><\/p>\n<\/blockquote>\n

Not one I\u2019d seen before! <\/p>\n

As with most support queries one of the first questions to ask is \u201cwhat has changed?\u201d and this particular client has a Sonicwall Email Security Appliance that had failed and been swapped out that same morning<\/p>\n

Looking through the rest of the NDR it was clear the issue was with the appliance.<\/p>\n

\n

Generating server: spam.invalid_sonicwall_gateway_domain.com <\/strong><\/p>\n<\/blockquote>\n

This was also a huge pointer as to what the issue was. <\/p>\n

The host name needs to be a fully qualified domain name but in this case it had just been set to \u201cspam\u201d <\/p>\n

\"image\"<\/a><\/p>\n

Once it was corrected (e.g spam.customer.com) and the device was rebooted all was well. <\/p>\n

I\u2019m not entirely sure how the host name ended up like that as I\u2019m sure that form won\u2019t allow you to enter a host name that isn\u2019t a fully qualified domain name. <\/p>\n

The device settings were restored from a backup so it\u2019s possible it was part of that but I\u2019m just making a guess on that part!<\/p>\n

Either way it was a simple enough fix and email went back to normal after that. <\/p>\n","protected":false},"excerpt":{"rendered":"

Yesterday I had a client report that certain emails were being bounced The SMTP error message was this 501 Syntactically invalid HELO argument(s) Not one I\u2019d seen before! As with most support queries one of the first questions to ask is \u201cwhat has changed?\u201d and this particular client has a Sonicwall Email Security Appliance that<\/p>\n

<\/span>Read More<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[48],"tags":[],"class_list":["post-1449","post","type-post","status-publish","format-standard","hentry","category-sonicwall"],"yoast_head":"\nSyntactically invalid HELO argument(s) - Andy's Techie Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/andyparkes.co.uk\/blog\/index.php\/2014\/09\/12\/syntactically-invalid-helo-arguments\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Syntactically invalid HELO argument(s) - Andy's Techie Blog\" \/>\n<meta property=\"og:description\" content=\"Yesterday I had a client report that certain emails were being bounced The SMTP error message was this 501 Syntactically invalid HELO argument(s) Not one I\u2019d seen before! 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