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Relay e AntiSpam
Colaboração: Rubens Queiroz de Almeida
Data de Publicação: 06 de Abril de 2000
Para determinar se seu servidor de correio eletrônico pode ser vítima do ataque de espertalhões e ser usado para distribuir milhares de mensagens de spam, utilize os serviços oferecidos por mail-abuse.net.
Faça simplesmente uma conexão telnet para mail-abuse.net, e este computador fará então diversos testes para determinar a vulnerabilidade da configuração do seu servidor.
Transcrevo abaixo um teste que fiz em um servidor, que felizmente passou em todos os testes. O nome e o endereço IP do servidor foi mudado para proteger os inocentes. :)
$ telnet mail-abuse.net Trying 204.152.184.74... Connected to mail-abuse.net. Escape character is '^]'. Connecting to 10.0.0.1 for anonymous test ... <<< 220 smtp.dominio.com.br ESMTP Sendmail 8.9.3/8.9.3; Fri, 31 Mar 2000 14:18:36 -0300 (EST) >>> HELO mail-abuse.org <<< 250 smtp.dominio.com.br Hello dante.mail-abuse.org [204.152.184.35], pleased to meet you Relay test 1 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest@mail-abuse.org> <<< 250 <spamtest@mail-abuse.org>... Sender ok >>> RCPT TO:<relaytest@mail-abuse.org> <<< 550 <relaytest@mail-abuse.org>... Relaying denied Relay test 2 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest> <<< 553 <spamtest>... Domain name required Relay test 3 >>> RSET <<< 250 Reset state >>> MAIL FROM:<> <<< 250 <>... Sender ok >>> RCPT TO:<relaytest@mail-abuse.org> <<< 550 <relaytest@mail-abuse.org>... Relaying denied Relay test 4 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest@smtp.dominio.com.br> <<< 250 <spamtest@smtp.dominio.com.br>... Sender ok >>> RCPT TO:<relaytest@mail-abuse.org> <<< 550 <relaytest@mail-abuse.org>... Relaying denied Relay test 5 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest@[10.0.0.1]> <<< 250 <spamtest@[10.0.0.1]>... Sender ok >>> RCPT TO:<relaytest@mail-abuse.org> <<< 550 <relaytest@mail-abuse.org>... Relaying denied Relay test 6 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest@smtp.dominio.com.br> <<< 250 <spamtest@smtp.dominio.com.br>... Sender ok >>> RCPT TO:<relaytest%mail-abuse.org@smtp.dominio.com.br> <<< 550 <relaytest%mail-abuse.org@smtp.dominio.com.br>... Relaying denied Relay test 7 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest@smtp.dominio.com.br> <<< 250 <spamtest@smtp.dominio.com.br>... Sender ok >>> RCPT TO:<relaytest%mail-abuse.org@smtp.dominio.com.br> <<< 550 <relaytest%mail-abuse.org@smtp.dominio.com.br>... Relaying denied Relay test 8 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest@smtp.dominio.com.br> <<< 250 <spamtest@smtp.dominio.com.br>... Sender ok >>> RCPT TO:<"relaytest@mail-abuse.org"> <<< 550 <"relaytest@mail-abuse.org">... Relaying denied Relay test 9 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest@smtp.dominio.com.br> <<< 250 <spamtest@smtp.dominio.com.br>... Sender ok >>> RCPT TO:<"relaytest%mail-abuse.org"> <<< 550 <"relaytest%mail-abuse.org">... Relaying denied Relay test 10 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest@smtp.dominio.com.br> <<< 250 <spamtest@smtp.dominio.com.br>... Sender ok >>> RCPT TO:<relaytest@mail-abuse.org@smtp.dominio.com.br> <<< 550 <relaytest@mail-abuse.org@smtp.dominio.com.br>... Relaying denied Relay test 11 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest@smtp.dominio.com.br> <<< 250 <spamtest@smtp.dominio.com.br>... Sender ok >>> RCPT TO:<"relaytest@mail-abuse.org"@smtp.dominio.com.br> <<< 550 <"relaytest@mail-abuse.org"@smtp.dominio.com.br>... Relaying denied Relay test 12 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest@smtp.dominio.com.br> <<< 250 <spamtest@smtp.dominio.com.br>... Sender ok >>> RCPT TO:<relaytest@mail-abuse.org@smtp.dominio.com.br> <<< 550 <relaytest@mail-abuse.org@smtp.dominio.com.br>... Relaying denied Relay test 13 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest@smtp.dominio.com.br> <<< 250 <spamtest@smtp.dominio.com.br>... Sender ok >>> RCPT TO:<@smtp.dominio.com.br:relaytest@mail-abuse.org> <<< 550 <@smtp.dominio.com.br:relaytest@mail-abuse.org>... Relaying denied Relay test 14 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest@smtp.dominio.com.br> <<< 250 <spamtest@smtp.dominio.com.br>... Sender ok >>> RCPT TO:<@smtp.dominio.com.br:relaytest@mail-abuse.org> <<< 550 <@smtp.dominio.com.br:relaytest@mail-abuse.org>... Relaying denied Relay test 15 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest@> <<< 553 <spamtest@>... Domain name required Relay test 16 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest@smtp.dominio.com.br> <<< 250 <spamtest@smtp.dominio.com.br>... Sender ok >>> RCPT TO:<mail-abuse.org!relaytest> <<< 550 <mail-abuse.org!relaytest>... User unknown Relay test 17 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest@smtp.dominio.com.br> <<< 250 <spamtest@smtp.dominio.com.br>... Sender ok >>> RCPT TO:<mail-abuse.org!relaytest@smtp.dominio.com.br> <<< 550 <mail-abuse.org!relaytest@smtp.dominio.com.br>... User unknown Relay test 18 >>> RSET <<< 250 Reset state >>> MAIL FROM:<spamtest@smtp.dominio.com.br> <<< 250 <spamtest@smtp.dominio.com.br>... Sender ok >>> RCPT TO:<mail-abuse.org!relaytest@smtp.dominio.com.br> <<< 550 <mail-abuse.org!relaytest@smtp.dominio.com.br>... User unknown Relay test result All tests performed, no relays accepted.
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Referências adicionais sobre os assuntos abordados neste site podem ser encontradas em nossa Bibliografia.
