diff --git a/include/types/dns.h b/include/types/dns.h
new file mode 100644
index 0000000..d5431a5
--- /dev/null
+++ b/include/types/dns.h
@@ -0,0 +1,210 @@
+/*
+ * include/types/dns.h
+ * This file provides structures and types for DNS.
+ *
+ * Copyright (C) 2014 Baptiste Assmann <bedis9@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, version 2.1
+ * exclusively.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#ifndef _TYPES_DNS_H
+#define _TYPES_DNS_H
+
+/*DNS maximum values */
+/*
+ * Maximum issued from RFC:
+ *  RFC 1035: https://www.ietf.org/rfc/rfc1035.txt chapter 2.3.4
+ *  RFC 2671: http://tools.ietf.org/html/rfc2671
+ */
+#define DNS_MAX_LABEL_SIZE	63
+#define DNS_MAX_NAME_SIZE	255
+#define DNS_MAX_UDP_MESSAGE	4096
+
+/* DNS error messages */
+#define DNS_TOO_LONG_FQDN	"hostname too long"
+#define DNS_LABEL_TOO_LONG	"one label too long"
+#define DNS_INVALID_CHARACTER	"found an invalid character"
+
+/* dns query class */
+#define DNS_RCLASS_IN		1	/* internet class */
+
+/* dns record types (non exhaustive list) */
+#define DNS_RTYPE_A		1	/* IPv4 address */
+#define DNS_RTYPE_CNAME		5	/* canonical name */
+#define DNS_RTYPE_AAAA		28	/* IPv6 address */
+#define DNS_RTYPE_ANY		255	/* all records */
+
+/* dns rcode values */
+#define DNS_RCODE_NO_ERROR	0	/* no error */
+#define DNS_RCODE_NX_DOMAIN	3	/* non existent domain */
+#define DNS_RCODE_REFUSED	5	/* query refused */
+
+/* DNS request or response header structure */
+struct dns_header {
+	unsigned short	id:16;		/* identifier */
+	unsigned char	rd :1;		/* recursion desired 0: no, 1: yes */
+	unsigned char	tc :1;		/* truncation 0:no, 1: yes */
+	unsigned char	aa :1;		/* authoritative answer 0: no, 1: yes */
+	unsigned char	opcode :4;	/* operation code */
+	unsigned char	qr :1;		/* query/response 0: query, 1: response */
+	unsigned char	rcode :4;	/* response code */
+	unsigned char	z :1;		/* no used */
+	unsigned char	ad :1;		/* authentic data */
+	unsigned char	cd :1;		/* checking disabled */
+	unsigned char	ra :1;		/* recursion available 0: no, 1: yes */
+	unsigned short	qdcount :16;	/* question count */
+	unsigned short	ancount :16;	/* answer count */
+	unsigned short	nscount :16;	/* authority count */
+	unsigned short	arcount :16;	/* additional count */
+};
+
+/* short structure to describe a DNS question */
+struct dns_question {
+	unsigned short	qtype;		/* question type */
+	unsigned short	qclass;		/* query class */
+};
+
+/*
+ * resolvers section and parameters. It is linked to the name servers
+ * servers points to it.
+ * current resolution are stored in a FIFO list.
+ */
+struct dns_resolvers {
+	struct list list;		/* resolvers list */
+	char *id;			/* resolvers unique identifier */
+	struct {
+		const char *file;	/* file where the section appears */
+		int line;		/* line where the section appears */
+	} conf;				/* config information */
+	struct list nameserver_list;	/* dns server list */
+	int count_nameservers;			/* total number of nameservers in a resolvers section */
+	int resolve_retries;		/* number of retries before giving up */
+	struct {			/* time to: */
+		int retry;		/*   wait for a response before retrying */
+	} timeout;
+	struct {			/* time to hold current data when */
+		int valid;		/*   a response is valid */
+	} hold;
+	struct task *t;			/* timeout management */
+	struct list curr_resolution;	/* current running resolutions */
+	struct eb_root query_ids;	/* tree to quickly lookup/retrieve query ids currently in use */
+					/* used by each nameserver, but stored in resolvers since there must */
+					/* be a unique relation between an eb_root and an eb_node (resolution) */
+};
+
+/*
+ * structure describing a name server used during name resolution.
+ * A name server belongs to a resolvers section.
+ */
+struct dns_nameserver {
+	struct list list;		/* nameserver chained list */
+	char *id;			/* nameserver unique identifier */
+	struct {
+		const char *file;	/* file where the section appears */
+		int line;		/* line where the section appears */
+	} conf;				/* config information */
+	struct dns_resolvers *resolvers;
+	struct dgram_conn *dgram;		/* transport layer */
+	struct sockaddr_storage addr;	/* IP address */
+	struct {			/* numbers relted to this name server: */
+		long int sent;		/* - queries sent */
+		long int valid;		/* - valid response */
+		long int update;	/* - valid response used to update server's IP */
+		long int cname;		/* - CNAME response requiring new resolution */
+		long int cname_error;	/* - error when resolving CNAMEs */
+		long int any_err;	/* - void response (usually because ANY qtype) */
+		long int nx;		/* - NX response */
+		long int timeout;	/* - queries which reached timeout */
+		long int refused;	/* - queries refused */
+		long int other;		/* - other type of response */
+		long int invalid;	/* - malformed DNS response */
+		long int too_big;	/* - too big response */
+		long int outdated;	/* - outdated response (server slower than the other ones) */
+	} counters;
+};
+
+/*
+ * resolution structure associated to single server and used to manage name resolution for
+ * this server.
+ * The only link between the resolution and a nameserver is through the query_id.
+ */
+struct dns_resolution {
+	struct list list;		/* resolution list */
+	struct dns_resolvers *resolvers;	/* resolvers section associated to this resolution */
+	void *requester;		/* owner of this name resolution */
+	int (*requester_cb)(struct dns_resolution *, struct dns_nameserver *, unsigned char *, int);
+					/* requester callback for valid response */
+	int (*requester_error_cb)(struct dns_resolution *, int);
+					/* requester callback, for error management */
+	char *hostname_dn;		/* server hostname in domain name label format */
+	int hostname_dn_len;		/* server domain name label len */
+	int resolver_family_priority;	/* which IP family should the resolver use when both are returned */
+	time_t last_resolution;		/* time of the lastest valid resolution */
+	time_t last_sent_packet;	/* time of the latest DNS packet sent */
+	time_t last_status_change;	/* time of the latest DNS resolution status change */
+	int query_id;			/* DNS query ID dedicated for this resolution */
+	struct eb32_node qid;		/* ebtree query id */
+	int query_type;			/* query type to send. By default DNS_RTYPE_ANY */
+	int status;			/* status of the resolution being processed RSLV_STATUS_* */
+	int step;			/* */
+	int try;			/* current resolution try */
+	int try_cname;			/* number of CNAME requests sent */
+	int nb_responses;		/* count number of responses received */
+};
+
+/* last resolution status code */
+enum {
+	RSLV_STATUS_NONE	= 0,	/* no resolution occured yet */
+	RSLV_STATUS_VALID,		/* no error */
+	RSLV_STATUS_INVALID,		/* invalid responses */
+	RSLV_STATUS_ERROR,		/* error */
+	RSLV_STATUS_NX,			/* NXDOMAIN */
+	RSLV_STATUS_REFUSED,		/* server refused our query */
+	RSLV_STATUS_TIMEOUT,		/* no response from DNS servers */
+	RSLV_STATUS_OTHER,		/* other errors */
+};
+
+/* current resolution step */
+enum {
+	RSLV_STEP_NONE		= 0,	/* nothing happening currently */
+	RSLV_STEP_RUNNING,		/* resolution is running */
+};
+
+/* return codes after analyzing a DNS response */
+enum {
+	DNS_RESP_VALID		= 0,	/* valid response */
+	DNS_RESP_INVALID,		/* invalid response (various type of errors can trigger it) */
+	DNS_RESP_ERROR,			/* DNS error code */
+	DNS_RESP_NX_DOMAIN,		/* resolution unsuccessful */
+	DNS_RESP_REFUSED,		/* DNS server refused to answer */
+	DNS_RESP_ANCOUNT_ZERO,		/* no answers in the response */
+	DNS_RESP_WRONG_NAME,		/* response does not match query name */
+	DNS_RESP_CNAME_ERROR,		/* error when resolving a CNAME in an atomic response */
+	DNS_RESP_TIMEOUT,		/* DNS server has not answered in time */
+};
+
+/* return codes after searching an IP in a DNS response buffer, using a family preference */
+enum {
+	DNS_UPD_NO 		= 1,	/* provided IP was found and preference is matched
+					 * OR provided IP found and preference is not matched, but no IP
+					 *    matching preference was found */
+	DNS_UPD_SRVIP_NOT_FOUND,	/* provided IP not found
+					 * OR provided IP found and preference is not match and an IP
+					 *    matching preference was found */
+	DNS_UPD_CNAME,			/* CNAME without any IP provided in the response */
+	DNS_UPD_NAME_ERROR,		/* name in the response did not match the query */
+};
+
+#endif /* _TYPES_DNS_H */
diff --git a/include/types/global.h b/include/types/global.h
index 2996dda..921ef83 100644
--- a/include/types/global.h
+++ b/include/types/global.h
@@ -222,6 +222,7 @@
 extern struct list global_listener_queue; /* list of the temporarily limited listeners */
 extern struct task *global_listener_queue_task;
 extern unsigned int warned;     /* bitfield of a few warnings to emit just once */
+extern struct list dns_resolvers;
 
 /* bit values to go with "warned" above */
 #define WARN_BLOCK_DEPRECATED       0x00000001