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Re: How to interpret CURLE_WEIRD_SERVER_REPLY?
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From: Patrick Monnerat via curl-library <curl-library_at_lists.haxx.se>
Date: Sat, 18 Oct 2025 21:14:23 +0200
On 10/18/25 9:04 PM, Patrick Schlangen via curl-library wrote:
> Did you try capturing a verbose / traffic log for this?
> Does it work when using curl from the command line?
It seems the code activates ther verbose output, but it has not been
posted. This is mandatory to have this to answer the initial question.
Blindy, I can already say PLAIN mechanism is used instead of the Eudora
LOGIN choice, as the former is preferred by curl over the latter.
I don't know if it's the problem, but CURLOPT_LOGIN_OPTIONS could have
been used to force LOGIN mechanism.
Patrick
> Best,
>
> Patrick
>
>> Am 18.10.2025 um 20:11 schrieb SherwoodP via curl-library <curl-library_at_lists.haxx.se>:
>>
>> BACKGROUND:
>> I am trying to use curl v8.6.0 on a Windows 11 system to send email to my POP3 server (att.com). AT&T uses "secure mail keys" for authentication.
>>
>> I can access AT&T's email web interface using a user name and password.
>> I can also access the same account with Eudora, which requires a secure mail key.
>>
>> USING CURL:
>> This is the curl C++20 code I am using to send a sample message:
>>
>> curl = curl_easy_init();
>> if (curl)
>> {
>> CURLcode code=curl_easy_setopt(curl, CURLOPT_URL, si .server);
>> code=curl_easy_setopt(curl, CURLOPT_USE_SSL, (long ) CURLUSESSL_ALL );
>> code = curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L); // Tell libcurl to *not* verify the peer
>> code = curl_easy_setopt(curl, CURLOPT_USERNAME, si .userName);
>> code = curl_easy_setopt(curl, CURLOPT_PASSWORD, si .pw);
>> code = curl_easy_setopt(curl, CURLOPT_MAIL_FROM, si .from);
>> recipients = curl_slist_append(recipients, si .to);
>> if (strlen( si .cc)) // cc: is optional
>> recipients = curl_slist_append(recipients, si .cc);
>> code = curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);
>> code = curl_easy_setopt(curl, CURLOPT_READFUNCTION, payload_source);
>> code = curl_easy_setopt(curl, CURLOPT_READDATA, &upload_ctx);
>> code = curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
>>
>> /* send the message (including headers) */
>> res = curl_easy_perform(curl);
>> }
>>
>> Structure si at the beginning of the code above contains
>> si{
>> server = "smtp://outbound.att.net:587"
>> userName = "MyUserName"
>> pw = "MySecureKey"
>> t = "ToEmailAddr"
>> from = "FromEmailAddr"
>> cc = "<info_at_example.org>"
>> messageID = "Communicate_000000006334"
>> subject = "Communicate test email"
>> nBodyLines = 10
>> body
>> [0] = "\tThe Germ"
>> [1] = ""
>> [2] = "A mighty creature is the germ,"
>> [3] = "Though smaller than a pachyderm."
>> [4] = "His customary dwelling place"
>> [5] = "Is deep within the human race."
>> [6] = "His childish pride he often pleases"
>> [7] = "By giving people strange diseases."
>> [8] = "Do you, my poppet, feel infirm?"
>> [9] = "You probably contain a germ."
>> };
>>
>> Running this code gives res = CURLE_WEIRD_SERVER_REPLY (8) "curl_easy_perform() failed: Weird server reply" if I use the AT&T secure key as si.pw, and "Login denied" if I use the AT&T password.
>>
>> To debug my usage of curl, I'd like to know what the "weird reply" is, or any other logging that curl provides. If the curl code is wrong in any way, or missing some detail of authentication, I'd appreciate advice on how to fix it.
>>
>> For comparison, the email client Eudora can successfully send email to this account. An excerpt from Eudora's debugging log is below. This shows that Eudora has successfully logged in.
>>
>> MAIN 16:14.54 Preparing messages to Send: 1
>> MAIN 16:14.54 RSET
>> MAIN 16:14.54 MAIL FROM:<FromEmailAddr>
>> MAIN 16:14.54 RCPT TO:<ToEmailAddr>
>> MAIN 16:14.54 DATA
>> MAIN 16:14.54 Test message
>> MAIN 16:14.54 Preparing messages to Send: 0
>> 21296 16:14.54 Open 67.195.12.35:465
>> 21296 32:14.54 Sent: " 16 03 01 00 F4 01 00 00 F0 03 03 C5 93 55 57 E6"
>> ...
>> 21296 64:14.54 Rcvd: " 16 03 03 13 2E 02 00"
>> ...
>> 21296 64:14.54 Rcvd: "220 smtp.mail.yahoo.com ESMTP ready\r\n"
>> 21296 32:14.54 Sent: "EHLO MyComputerName.MyEmailDomain\r\n"
>> 21296 64:14.54 Rcvd: "250-hermes--production-gq1-6b8576c5cf-gs5mr Hello MyComputerName.MyEmailDomain [xx.xx.xx.xx])\r\n"
>> 21296 64:14.54 Rcvd: "250-PIPELINING\r\n"
>> 21296 64:14.54 Rcvd: "250-ENHANCEDSTATUSCODES\r\n"
>> 21296 64:14.54 Rcvd: "250-8BITMIME\r\n"
>> 21296 64:14.54 Rcvd: "250-SIZE 41697280\r\n"
>> 21296 64:14.54 Rcvd: "250 AUTH PLAIN LOGIN XOAUTH2 OAUTHBEARER\r\n"
>> 21296 32:14.54 Sent: "AUTH LOGIN\r\n"
>> 21296 64:14.54 Rcvd: "334 xxxxxxxxxxxx\r\n"
>> 21296 32:14.54 Sent: "xxxxxxxxxxxxxxxxxxxxxxxxxxxx\r\n"
>> 21296 64:14.54 Rcvd: "334 xxxxxxxxxxxx\r\n"
>> 21296 32:14.54 Sent: "xxxxxxxxxxxxxxxxxxxxxxxx\r\n"
>> 21296 64:14.56 Rcvd: "235 2.7.0 Authentication successful\r\n"
>> 21296 32:14.56 Sent: "RSET\r\n"
>> 21296 64:14.56 Rcvd: "250 2.0.0 OK\r\n"
>> 21296 32:14.56 Sent: "MAIL FROM:<FromEmailAddr>\r\n"
>> 21296 64:14.56 Rcvd: "250 2.1.0 Sender <FromEmailAddr> OK\r\n"
>> 21296 32:14.56 Sent: "RCPT TO:<ToEmailAddr>\r\n"
>> 21296 64:14.56 Rcvd: "250 2.1.5 Recipient <ToEmailAddr> OK\r\n"
>> 21296 32:14.56 Sent: "DATA\r\n"
>> 21296 64:14.56 Rcvd: "354 Ok Send data ending with <CRLF>.<CRLF>\r\n"
>> 21296 32:14.56 Sent: "X-Mailer: QUALCOMM Windows Eudora Version 7.1.0.9\r\n"
>> 21296 32:14.56 Sent: "Date: Sat, 18 Oct 2025 10:53:07 -0700\r\n"
>> 21296 32:14.56 Sent: "To: ToEmailAddr\r\n"
>> 21296 32:14.56 Sent: "From: FromEmailAddr\r\n"
>> 21296 32:14.56 Sent: "Subject: Test message\r\n"
>> 21296 32:14.56 Sent: "Mime-Version: 1.0\r\n"
>> 21296 32:14.56 Sent: "Content-Type: text/plain; charset="us-ascii"; format=flowed\r\n"
>> 21296 32:14.56 Sent: "\r\n"
>> 21296 32:14.56 Sent: "Body of message.\r\n"
>> 21296 32:14.56 Sent: "\r\n"
>> 21296 32:14.56 Sent: ".\r\n"
>> 21296 64:14.57 Rcvd: "250 OK , completed\r\n"
>> 21296 32:14.57 Sent: "QUIT\r\n"
>> 21296 64:14.57 Rcvd: "221 Service Closing transmission\r\n"
>>
>>
>>
>>
>> --
>> Unsubscribe: https://lists.haxx.se/mailman/listinfo/curl-library
>> Etiquette: https://curl.se/mail/etiquette.html
Date: Sat, 18 Oct 2025 21:14:23 +0200
On 10/18/25 9:04 PM, Patrick Schlangen via curl-library wrote:
> Did you try capturing a verbose / traffic log for this?
> Does it work when using curl from the command line?
It seems the code activates ther verbose output, but it has not been
posted. This is mandatory to have this to answer the initial question.
Blindy, I can already say PLAIN mechanism is used instead of the Eudora
LOGIN choice, as the former is preferred by curl over the latter.
I don't know if it's the problem, but CURLOPT_LOGIN_OPTIONS could have
been used to force LOGIN mechanism.
Patrick
> Best,
>
> Patrick
>
>> Am 18.10.2025 um 20:11 schrieb SherwoodP via curl-library <curl-library_at_lists.haxx.se>:
>>
>> BACKGROUND:
>> I am trying to use curl v8.6.0 on a Windows 11 system to send email to my POP3 server (att.com). AT&T uses "secure mail keys" for authentication.
>>
>> I can access AT&T's email web interface using a user name and password.
>> I can also access the same account with Eudora, which requires a secure mail key.
>>
>> USING CURL:
>> This is the curl C++20 code I am using to send a sample message:
>>
>> curl = curl_easy_init();
>> if (curl)
>> {
>> CURLcode code=curl_easy_setopt(curl, CURLOPT_URL, si .server);
>> code=curl_easy_setopt(curl, CURLOPT_USE_SSL, (long ) CURLUSESSL_ALL );
>> code = curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L); // Tell libcurl to *not* verify the peer
>> code = curl_easy_setopt(curl, CURLOPT_USERNAME, si .userName);
>> code = curl_easy_setopt(curl, CURLOPT_PASSWORD, si .pw);
>> code = curl_easy_setopt(curl, CURLOPT_MAIL_FROM, si .from);
>> recipients = curl_slist_append(recipients, si .to);
>> if (strlen( si .cc)) // cc: is optional
>> recipients = curl_slist_append(recipients, si .cc);
>> code = curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);
>> code = curl_easy_setopt(curl, CURLOPT_READFUNCTION, payload_source);
>> code = curl_easy_setopt(curl, CURLOPT_READDATA, &upload_ctx);
>> code = curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
>>
>> /* send the message (including headers) */
>> res = curl_easy_perform(curl);
>> }
>>
>> Structure si at the beginning of the code above contains
>> si{
>> server = "smtp://outbound.att.net:587"
>> userName = "MyUserName"
>> pw = "MySecureKey"
>> t = "ToEmailAddr"
>> from = "FromEmailAddr"
>> cc = "<info_at_example.org>"
>> messageID = "Communicate_000000006334"
>> subject = "Communicate test email"
>> nBodyLines = 10
>> body
>> [0] = "\tThe Germ"
>> [1] = ""
>> [2] = "A mighty creature is the germ,"
>> [3] = "Though smaller than a pachyderm."
>> [4] = "His customary dwelling place"
>> [5] = "Is deep within the human race."
>> [6] = "His childish pride he often pleases"
>> [7] = "By giving people strange diseases."
>> [8] = "Do you, my poppet, feel infirm?"
>> [9] = "You probably contain a germ."
>> };
>>
>> Running this code gives res = CURLE_WEIRD_SERVER_REPLY (8) "curl_easy_perform() failed: Weird server reply" if I use the AT&T secure key as si.pw, and "Login denied" if I use the AT&T password.
>>
>> To debug my usage of curl, I'd like to know what the "weird reply" is, or any other logging that curl provides. If the curl code is wrong in any way, or missing some detail of authentication, I'd appreciate advice on how to fix it.
>>
>> For comparison, the email client Eudora can successfully send email to this account. An excerpt from Eudora's debugging log is below. This shows that Eudora has successfully logged in.
>>
>> MAIN 16:14.54 Preparing messages to Send: 1
>> MAIN 16:14.54 RSET
>> MAIN 16:14.54 MAIL FROM:<FromEmailAddr>
>> MAIN 16:14.54 RCPT TO:<ToEmailAddr>
>> MAIN 16:14.54 DATA
>> MAIN 16:14.54 Test message
>> MAIN 16:14.54 Preparing messages to Send: 0
>> 21296 16:14.54 Open 67.195.12.35:465
>> 21296 32:14.54 Sent: " 16 03 01 00 F4 01 00 00 F0 03 03 C5 93 55 57 E6"
>> ...
>> 21296 64:14.54 Rcvd: " 16 03 03 13 2E 02 00"
>> ...
>> 21296 64:14.54 Rcvd: "220 smtp.mail.yahoo.com ESMTP ready\r\n"
>> 21296 32:14.54 Sent: "EHLO MyComputerName.MyEmailDomain\r\n"
>> 21296 64:14.54 Rcvd: "250-hermes--production-gq1-6b8576c5cf-gs5mr Hello MyComputerName.MyEmailDomain [xx.xx.xx.xx])\r\n"
>> 21296 64:14.54 Rcvd: "250-PIPELINING\r\n"
>> 21296 64:14.54 Rcvd: "250-ENHANCEDSTATUSCODES\r\n"
>> 21296 64:14.54 Rcvd: "250-8BITMIME\r\n"
>> 21296 64:14.54 Rcvd: "250-SIZE 41697280\r\n"
>> 21296 64:14.54 Rcvd: "250 AUTH PLAIN LOGIN XOAUTH2 OAUTHBEARER\r\n"
>> 21296 32:14.54 Sent: "AUTH LOGIN\r\n"
>> 21296 64:14.54 Rcvd: "334 xxxxxxxxxxxx\r\n"
>> 21296 32:14.54 Sent: "xxxxxxxxxxxxxxxxxxxxxxxxxxxx\r\n"
>> 21296 64:14.54 Rcvd: "334 xxxxxxxxxxxx\r\n"
>> 21296 32:14.54 Sent: "xxxxxxxxxxxxxxxxxxxxxxxx\r\n"
>> 21296 64:14.56 Rcvd: "235 2.7.0 Authentication successful\r\n"
>> 21296 32:14.56 Sent: "RSET\r\n"
>> 21296 64:14.56 Rcvd: "250 2.0.0 OK\r\n"
>> 21296 32:14.56 Sent: "MAIL FROM:<FromEmailAddr>\r\n"
>> 21296 64:14.56 Rcvd: "250 2.1.0 Sender <FromEmailAddr> OK\r\n"
>> 21296 32:14.56 Sent: "RCPT TO:<ToEmailAddr>\r\n"
>> 21296 64:14.56 Rcvd: "250 2.1.5 Recipient <ToEmailAddr> OK\r\n"
>> 21296 32:14.56 Sent: "DATA\r\n"
>> 21296 64:14.56 Rcvd: "354 Ok Send data ending with <CRLF>.<CRLF>\r\n"
>> 21296 32:14.56 Sent: "X-Mailer: QUALCOMM Windows Eudora Version 7.1.0.9\r\n"
>> 21296 32:14.56 Sent: "Date: Sat, 18 Oct 2025 10:53:07 -0700\r\n"
>> 21296 32:14.56 Sent: "To: ToEmailAddr\r\n"
>> 21296 32:14.56 Sent: "From: FromEmailAddr\r\n"
>> 21296 32:14.56 Sent: "Subject: Test message\r\n"
>> 21296 32:14.56 Sent: "Mime-Version: 1.0\r\n"
>> 21296 32:14.56 Sent: "Content-Type: text/plain; charset="us-ascii"; format=flowed\r\n"
>> 21296 32:14.56 Sent: "\r\n"
>> 21296 32:14.56 Sent: "Body of message.\r\n"
>> 21296 32:14.56 Sent: "\r\n"
>> 21296 32:14.56 Sent: ".\r\n"
>> 21296 64:14.57 Rcvd: "250 OK , completed\r\n"
>> 21296 32:14.57 Sent: "QUIT\r\n"
>> 21296 64:14.57 Rcvd: "221 Service Closing transmission\r\n"
>>
>>
>>
>>
>> --
>> Unsubscribe: https://lists.haxx.se/mailman/listinfo/curl-library
>> Etiquette: https://curl.se/mail/etiquette.html
-- Unsubscribe: https://lists.haxx.se/mailman/listinfo/curl-library Etiquette: https://curl.se/mail/etiquette.htmlReceived on 2025-10-18