I'm using Exim as my server my MTA , one of my vhosts client has an issue with his outgoing email messages uncluding attachments it never reach the outside , i tried from the webmail it works , i think it could a mail client issue , any advices ? smtp auth problem? Haris: some details ? either its smtp auth or mail relay not permitted issue Haris: are these , client side issues ? f00bar80: ..hardly smtp auth means, authentication from a client who is trying to send mail through your server ..who is trying to send mail through your server, before your server sends it Haris: and what about mail relay ? f00bar80: Read on relay_domains and relay_to_domains like local_domains, there's a relay_domains Haris: sorry :) , is it mail client issue or MTA one ? MTA If your client received any errors on the client side Haris: so why espec , this account ? Then it maybe a client side issue but so far, you haven't mentioned any such case MTA == Mtail Transport Agent (exim, qmail, sendmail.. ) Haris: the client never received any bounce messages , not bounce messages while the client was trying to send mail through your server, did they get any error messages? Haris: again i'm asking , if it's an MTA issue , then why only this account and any other accounts correctly plus , the web mail for the same account works without any issues through webmail, it will always work, because by default localhost is allowed to relay f00bar80: Check if this client's domain name is in relay_domains Haris: any guide/pointer to these relay_domains or relay to domain ? Haris: and how to check f00bar80: find relay_domains or relay_to_domains keyword in your exim config and also in the documentation download the pdf version of docs Haris: any link ? http://www.exim.org/exim-pdf-current/doc/spec.pdf http://www.exim.org/exim-html-current/doc/html/spec_html/index.html <- if you want to read online http://www.exim.org/