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Strange Problem with SMTP-Auth on Cisco ESA (Async-OS: 14.2.3-027)

Hallowelt
Level 1
Level 1

Dear all,

while debugging SMTP-Authentication-Problems I notice the following strange behaviour:

connecting with "openssl s_client -connect server.name:587 -starttls smtp"

Trying username "Anton" (Base64 = QW50b24=)

---------------
AUTH LOGIN
334 VXNlcm5hbWU6
QW50b24=
DONE
---------------
-> ESA closes connection unexpectedly

Trying Username "A" (QQ==)
--------------------------
auth login
334 VXNlcm5hbWU6
QQ==
DONE
--------------------------
Same error (unexpected close) as above
Trying username "D" (RA==)
--------------------------
auth login
334 VXNlcm5hbWU6
RA==
334 UGFzc3dvcmQ6
RA==
535 #5.7.0 Authentication failed
--------------------------
-> That's the expected behaviour, as the user does not exist

Further tests show, that usernames beginning with (@,A,B,C) giving an encoded Base64-String starting with "Q" lead to the same erroneous behaviour.
The same happens, when trying to authenticate with a password starting in cleartext with (@,A,B,C)

Any idea?

Thanks,
Harald

1 Reply 1

stkandpa
Cisco Employee
Cisco Employee

Hey Hallowelt,

 

As this seems to be a specific problem with you environment, I will suggest you to open a TAC case with Cisco and the team will help you resolve it. 

Adding the methods to open a case(You can use any one of them):

1.  Go to the TAC website > My support > Open/View Cases > Open New Case ;

2.  Send an email to tac@cisco.com and make sure you include your CCO login;

3.  Call them;

 

Regards

Stuti Kandpal

 

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