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We are doing client authenticatie using certificates in Apache. We want to pass the value in the subject.serialNumber of the certificate to the application server. It seems every field of the suject can be retrieved and passed using SSL_CLIENT_S_DN_, except for subject.serialNumber. Does anyone know how the value can be extracted?

Regards, nidkil

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According to this document, SSL_CLIENT_M_SERIAL contains the client certificate serial number. Is that what you're after? –  larsks Sep 6 '12 at 0:41
@larsks, lets assume that he is using a version of Apache newer then 1.3 and send him to the official 2.2 documentation instead. httpd.apache.org/docs/2.2/mod/mod_ssl.html –  Zoredache Sep 6 '12 at 1:47
Sure, although my quick read indicates that it provides an identical answer... –  larsks Sep 6 '12 at 13:34
Hi guys, sorry for the delayed response. We are using version 2.2. The field you are referencing to is the certificates serial number. We are trying to retrieve the serialNumber that is part of the subject, hence subject.serialNumber. Any ideas? –  nidkil Sep 26 '12 at 18:55

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