diff --git a/configure.ac b/configure.ac
index 3cf8abd7c..6d4264e68 100644
--- a/configure.ac
+++ b/configure.ac
@@ -962,6 +962,7 @@ AC_HELP_STRING([--with-ssl-libs=[[[DIR]]]], [Path to SSL library directory]),
 ], [])
 
 RB_CHK_SYSHEADER(openssl/err.h, [OPENSSL_ERR_H])
+RB_CHK_SYSHEADER(openssl/asn1.h, [OPENSSL_ASN1_H])
 RB_CHK_SYSHEADER(openssl/sha.h, [OPENSSL_SHA_H])
 RB_CHK_SYSHEADER(openssl/hmac.h, [OPENSSL_HMAC_H])
 RB_CHK_SYSHEADER(openssl/ssl.h, [OPENSSL_SSL_H])
diff --git a/ircd/openssl.cc b/ircd/openssl.cc
index 7d7b72a86..d387871a0 100644
--- a/ircd/openssl.cc
+++ b/ircd/openssl.cc
@@ -9,6 +9,7 @@
 // full license for this software is available in the LICENSE file.
 
 #include <RB_INC_OPENSSL_ERR_H
+#include <RB_INC_OPENSSL_ASN1_H
 #include <RB_INC_OPENSSL_SHA_H
 #include <RB_INC_OPENSSL_HMAC_H
 #include <RB_INC_OPENSSL_SSL_H