diff --git a/authd/Makefile.am b/authd/Makefile.am
index ef2c44a4..d6033e05 100644
--- a/authd/Makefile.am
+++ b/authd/Makefile.am
@@ -14,6 +14,7 @@ authd_SOURCES =	\
 	reslist.c \
 	providers/blacklist.c \
 	providers/ident.c \
-	providers/rdns.c
+	providers/rdns.c \
+	providers/opm.c
 
 authd_LDADD = ../librb/src/librb.la
diff --git a/authd/provider.c b/authd/provider.c
index f6413c4d..3a7abf6e 100644
--- a/authd/provider.c
+++ b/authd/provider.c
@@ -118,6 +118,7 @@ init_providers(void)
 	load_provider(&rdns_provider);
 	load_provider(&ident_provider);
 	load_provider(&blacklist_provider);
+	load_provider(&opm_provider);
 }
 
 /* Terminate all providers */
diff --git a/authd/provider.h b/authd/provider.h
index 80fbf049..ca06c01c 100644
--- a/authd/provider.h
+++ b/authd/provider.h
@@ -99,6 +99,7 @@ extern rb_dictionary *auth_clients;
 extern struct auth_provider rdns_provider;
 extern struct auth_provider ident_provider;
 extern struct auth_provider blacklist_provider;
+extern struct auth_provider opm_provider;
 
 void load_provider(struct auth_provider *provider);
 void unload_provider(struct auth_provider *provider);
diff --git a/authd/providers/opm.c b/authd/providers/opm.c
new file mode 100644
index 00000000..24f6db74
--- /dev/null
+++ b/authd/providers/opm.c
@@ -0,0 +1,575 @@
+/* authd/providers/opm.c - small open proxy monitor
+ * Copyright (c) 2016 Elizabeth Myers <elizabeth@interlinked.me>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice is present in all copies.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <netinet/tcp.h>
+
+#include "stdinc.h"
+#include "setup.h"
+#include "authd.h"
+#include "notice.h"
+#include "provider.h"
+
+#define OPM_READSIZE 128
+
+typedef enum protocol_t
+{
+	PROTO_NONE,
+	PROTO_SOCKS4,
+	PROTO_SOCKS5,
+} protocol_t;
+
+struct opm_lookup
+{
+	rb_dlink_list scans;	/* List of scans */
+};
+
+struct opm_proxy
+{
+	const char *note;
+	protocol_t proto;
+	uint16_t port;
+};
+
+struct opm_scan
+{
+	struct auth_client *auth;
+
+	struct opm_proxy *proxy;
+	rb_fde_t *F;		/* fd for scan */
+
+	rb_dlink_node node;
+};
+
+struct opm_listener
+{
+	char ip[HOSTIPLEN];
+	uint16_t port;
+	struct sockaddr_storage addr;
+	rb_fde_t *F;
+};
+
+/* Proxies that we scan for */
+static struct opm_proxy opm_proxy_scans[] =
+{
+	{ "socks4-1080",	PROTO_SOCKS4,		1080  },
+	{ "socks5-1080",	PROTO_SOCKS5,		1080  },
+	{ "socks4-80",		PROTO_SOCKS4,		80    },
+	{ "socks5-80",		PROTO_SOCKS5,		80    },
+	{ "socks4-8080",	PROTO_SOCKS4,		8080  },
+	{ "socks5-8080",	PROTO_SOCKS5,		8080  },
+	{ NULL,			PROTO_NONE,		0     }
+};
+
+
+static ACCB accept_opm;
+static PF read_opm_reply;
+
+static CNCB socks4_connected;
+static CNCB socks5_connected;
+
+static void opm_cancel(struct auth_client *auth);
+
+static int opm_timeout = 5;
+static bool opm_enable = false;
+
+#define LISTEN_IPV4 0
+#define LISTEN_IPV6 1
+
+/* IPv4 and IPv6 */
+static struct opm_listener listeners[2];
+
+
+static void
+read_opm_reply(rb_fde_t *F, void *data)
+{
+	struct auth_client *auth = data;
+	struct opm_lookup *lookup;
+	char readbuf[OPM_READSIZE];
+	ssize_t len;
+
+	if(auth == NULL || (lookup = auth->data[PROVIDER_OPM]) == NULL)
+	{
+		rb_close(F);
+		return;
+	}
+
+	if((len = rb_read(F, readbuf, sizeof(readbuf))) < 0 && rb_ignore_errno(errno))
+	{
+		rb_setselect(F, RB_SELECT_READ, read_opm_reply, auth);
+		return;
+	}
+	else if(len <= 0)
+	{
+		/* Dead */
+		rb_close(F);
+		return;
+	}
+
+	for(struct opm_proxy *proxy = opm_proxy_scans; proxy->note != NULL; proxy++)
+	{
+		if(strncmp(proxy->note, readbuf, sizeof(readbuf)) != 0)
+			/* Nope */
+			continue;
+
+		/* If we get here we have an open proxy */
+		reject_client(auth, PROVIDER_OPM, readbuf, "Open proxy detected");
+		opm_cancel(auth);
+		break;
+	}
+
+	rb_close(F);
+}
+
+static void
+accept_opm(rb_fde_t *F, int status, struct sockaddr *addr, rb_socklen_t len, void *data)
+{
+	struct auth_client *auth = NULL;
+	struct opm_listener *listener = data;
+	struct rb_sockaddr_storage s_addr;
+	unsigned int llen = sizeof(struct rb_sockaddr_storage);
+	rb_dictionary_iter iter;
+
+	if(status != 0 || listener == NULL)
+	{
+		rb_close(F);
+		return;
+	}
+
+	if(getsockname(rb_get_fd(F), (struct sockaddr *)&s_addr, &llen))
+	{
+		/* This can happen if the client goes away after accept */
+		rb_close(F);
+		return;
+	}
+
+	/* Correlate connection with client(s) */
+	RB_DICTIONARY_FOREACH(auth, &iter, auth_clients)
+	{
+		if(GET_SS_FAMILY(&auth->c_addr) != GET_SS_FAMILY(&s_addr))
+			continue;
+
+		/* Compare the addresses */
+		switch(GET_SS_FAMILY(&s_addr))
+		{
+		case AF_INET:
+			{
+				struct sockaddr_in *s = (struct sockaddr_in *)&s_addr, *c = (struct sockaddr_in *)&auth->c_addr;
+
+				if(s->sin_addr.s_addr == c->sin_addr.s_addr)
+				{
+					/* Match... check if it's real */
+					rb_setselect(F, RB_SELECT_READ, read_opm_reply, auth);
+					return;
+				}
+				break;
+			}
+#ifdef RB_IPV6
+		case AF_INET6:
+			{
+				struct sockaddr_in6 *s = (struct sockaddr_in6 *)&s_addr, *c = (struct sockaddr_in6 *)&auth->c_addr;
+
+				if(memcmp(s->sin6_addr.s6_addr, c->sin6_addr.s6_addr, 16) == 0)
+				{
+					rb_setselect(F, RB_SELECT_READ, read_opm_reply, auth);
+					return;
+				}
+				break;
+			}
+#endif
+		default:
+			warn_opers(L_CRIT, "OPM: unknown address type in listen function");
+			exit(EX_PROVIDER_ERROR);
+		}
+	}
+
+	/* We don't care about the socket if we get here */
+	rb_close(F);
+}
+
+/* Scanners */
+
+static void
+socks4_connected(rb_fde_t *F, int error, void *data)
+{
+	struct opm_scan *scan = data;
+	struct opm_lookup *lookup;
+	struct auth_client *auth;
+	uint8_t sendbuf[9]; /* Size we're building */
+	uint8_t *c = sendbuf;
+	ssize_t ret;
+
+	if(scan == NULL || (auth = scan->auth) == NULL || (lookup = auth->data[PROVIDER_OPM]) == NULL)
+		return;
+
+	if(error || !opm_enable)
+		goto end;
+
+	memcpy(c, "\x04\x01", 2); c += 2; /* Socks version 4, connect command */
+
+	switch(GET_SS_FAMILY(&auth->c_addr))
+	{
+	case AF_INET:
+		if(listeners[LISTEN_IPV4].F == NULL)
+			/* They cannot respond to us */
+			goto end;
+
+		memcpy(c, &(((struct sockaddr_in *)&listeners[LISTEN_IPV4].addr)->sin_port), 2); c += 2; /* Port */
+		memcpy(c, &(((struct sockaddr_in *)&listeners[LISTEN_IPV4].addr)->sin_addr.s_addr), 4); c += 4; /* Address */
+		break;
+#ifdef RB_IPV6
+	case AF_INET6:
+	/* socks4 doesn't support IPv6 */
+#endif
+	default:
+		goto end;
+	}
+
+	*c = '\x00'; /* No userid */
+
+	/* Send header */
+	if(rb_write(scan->F, sendbuf, sizeof(sendbuf)) < 0)
+		goto end;
+
+	/* Send note */
+	if(rb_write(scan->F, scan->proxy->note, strlen(scan->proxy->note) + 1) < 0)
+		goto end;
+
+end:
+	rb_close(scan->F);
+	rb_dlinkDelete(&scan->node, &lookup->scans);
+	rb_free(scan);
+}
+
+static void
+socks5_connected(rb_fde_t *F, int error, void *data)
+{
+	struct opm_scan *scan = data;
+	struct opm_lookup *lookup; 
+	struct opm_listener *listener;
+	struct auth_client *auth;
+	uint8_t sendbuf[25]; /* Size we're building */
+	uint8_t *c = sendbuf;
+	ssize_t ret;
+
+	if(scan == NULL || (auth = scan->auth) == NULL || (lookup = auth->data[PROVIDER_OPM]) == NULL)
+		return;
+
+	if(error || !opm_enable)
+		goto end;
+
+	/* Build the version header and socks request
+	 * version header (3 bytes): version, number of auth methods, auth type (0 for none) 
+	 * connect req (3 bytes): version, command (1 = connect), reserved (0)
+	 */
+	memcpy(c, "\x05\x01\x00\x05\x01\x00", 6); c += 6;
+
+	switch(GET_SS_FAMILY(&auth->c_addr))
+	{
+	case AF_INET:
+		listener = &listeners[LISTEN_IPV4];
+		if(!listener->F)
+			goto end;
+
+		*(c++) = '\x01'; /* Address type (1 = IPv4) */
+		memcpy(c, &(((struct sockaddr_in *)&listener->addr)->sin_addr.s_addr), 4); c += 4;/* Address */
+		memcpy(c, &(((struct sockaddr_in *)&listener->addr)->sin_port), 2); c += 2; /* Port */
+		break;
+#ifdef RB_IPV6
+	case AF_INET6:
+		listener = &listeners[LISTEN_IPV6];
+		if(!listener->F)
+			goto end;
+
+		*(c++) = '\x04'; /* Address type (4 = IPv6) */
+		memcpy(c, ((struct sockaddr_in6 *)&listener->addr)->sin6_addr.s6_addr, 16); c += 16; /* Address */
+		memcpy(c, &(((struct sockaddr_in6 *)&listener->addr)->sin6_port), 2); c += 2; /* Port */
+		break;
+#endif
+	default:
+		goto end;
+	}
+
+	/* Send header */
+	if(rb_write(scan->F, sendbuf, (size_t)(sendbuf - c)) <= 0)
+		goto end;
+
+	/* Now the note in a separate write */
+	if(rb_write(scan->F, scan->proxy->note, strlen(scan->proxy->note) + 1) <= 0)
+		goto end;
+
+end:
+	rb_close(scan->F);
+	rb_dlinkDelete(&scan->node, &lookup->scans);
+	rb_free(scan);
+}
+
+/* Establish connections */
+static inline void
+establish_connection(struct auth_client *auth, struct opm_proxy *proxy)
+{
+	struct opm_lookup *lookup = auth->data[PROVIDER_OPM];
+	struct opm_listener *listener;
+	struct opm_scan *scan = rb_malloc(sizeof(struct opm_scan));
+	struct sockaddr_storage c_a, l_a;
+	int opt = 1;
+	CNCB *callback;
+
+	switch(proxy->proto)
+	{
+	case PROTO_SOCKS4:
+		callback = socks4_connected;
+		break;
+	case PROTO_SOCKS5:
+		callback = socks5_connected;
+		break;
+	default:
+		return;
+	}
+
+#ifdef RB_IPV6
+	if(GET_SS_FAMILY(&auth->c_addr) == AF_INET6)
+		listener = &listeners[LISTEN_IPV6];
+	else
+#endif
+		listener = &listeners[LISTEN_IPV4];
+
+	c_a = auth->c_addr;	/* Client */
+	l_a = listener->addr;	/* Listener */
+
+	scan->auth = auth;
+	scan->proxy = proxy;
+	if((scan->F = rb_socket(GET_SS_FAMILY(&auth->c_addr), SOCK_STREAM, 0, proxy->note)) == NULL)
+	{
+		warn_opers(L_CRIT, "OPM: could not create OPM socket (proto %s): %s", proxy->note, strerror(errno));
+		rb_free(scan);
+		return;
+	}
+
+	/* Disable Nagle's algorithim - buffering could affect scans */
+	(void)setsockopt(rb_get_fd(scan->F), IPPROTO_TCP, TCP_NODELAY, (char *)&opt, sizeof(opt));
+
+        /* Set the ports correctly */
+#ifdef RB_IPV6
+	if(GET_SS_FAMILY(&l_a) == AF_INET6)
+		((struct sockaddr_in6 *)&l_a)->sin6_port = 0;
+	else
+#endif
+		((struct sockaddr_in *)&l_a)->sin_port = 0;
+
+#ifdef RB_IPV6
+	if(GET_SS_FAMILY(&c_a) == AF_INET6)
+		((struct sockaddr_in6 *)&c_a)->sin6_port = ((struct sockaddr_in6 *)&listener->addr)->sin6_port;
+	else
+#endif
+		((struct sockaddr_in *)&c_a)->sin_port = ((struct sockaddr_in *)&listener->addr)->sin_port;
+
+	rb_dlinkAdd(scan, &scan->node, &lookup->scans);
+	rb_connect_tcp(scan->F,
+			(struct sockaddr *)&c_a,
+			(struct sockaddr *)&l_a,
+			GET_SS_LEN(&l_a),
+			callback, scan, opm_timeout);
+}
+
+static void
+opm_destroy(void)
+{
+	struct auth_client *auth;
+	rb_dictionary_iter iter;
+
+	/* Nuke all opm lookups */
+	RB_DICTIONARY_FOREACH(auth, &iter, auth_clients)
+	{
+		opm_cancel(auth);
+	}
+}
+
+static bool
+opm_start(struct auth_client *auth)
+{
+	struct opm_lookup *lookup = rb_malloc(sizeof(struct opm_lookup));
+
+	if(!opm_enable)
+	{
+		notice_client(auth->cid, "*** Proxy scanning disabled, not scanning");
+		return true;
+	}
+
+	auth->data[PROVIDER_OPM] = lookup = rb_malloc(sizeof(struct opm_lookup));
+	auth->timeout[PROVIDER_OPM] = rb_current_time() + opm_timeout;
+
+	for(struct opm_proxy *proxy = opm_proxy_scans; proxy->note != NULL; proxy++)
+		establish_connection(auth, proxy);
+
+	notice_client(auth->cid, "*** Scanning for open proxies...");
+	set_provider_on(auth, PROVIDER_OPM);
+
+	return true;
+}
+
+static void
+opm_cancel(struct auth_client *auth)
+{
+	struct opm_lookup *lookup = auth->data[PROVIDER_OPM];
+
+	if(lookup != NULL)
+	{
+		rb_dlink_node *ptr, *nptr;
+
+		RB_DLINK_FOREACH_SAFE(ptr, nptr, lookup->scans.head)
+		{
+			struct opm_scan *scan = ptr->data;
+
+			rb_close(scan->F);
+			rb_free(scan);
+		}
+
+		rb_free(lookup);
+		provider_done(auth, PROVIDER_OPM);
+	}
+}
+
+static void
+add_conf_opm_timeout(const char *key __unused, int parc __unused, const char **parv)
+{
+	int timeout = atoi(parv[0]);
+
+	if(timeout < 0)
+	{
+		warn_opers(L_CRIT, "opm: opm timeout < 0 (value: %d)", timeout);
+		return;
+	}
+
+	opm_timeout = timeout;
+}
+
+static void
+set_opm_enabled(const char *key __unused, int parc __unused, const char **parv)
+{
+	if(listeners[LISTEN_IPV4].F != NULL || listeners[LISTEN_IPV6].F != NULL)
+		opm_enable = (*parv[0] == '1');
+	else
+		/* No listener, no point... */
+		opm_enable = false;
+}
+
+static void
+set_opm_listener(const char *key __unused, int parc __unused, const char **parv)
+{
+	struct auth_client *auth;
+	struct sockaddr_storage addr;
+	struct opm_listener *listener;
+	int port = atoi(parv[1]), opt = 1;
+	rb_dictionary_iter iter;
+	rb_fde_t *F;
+	size_t i;
+
+	if(port > 65535 || port <= 0 || !rb_inet_pton_sock(parv[0], (struct sockaddr *)&addr))
+	{
+		warn_opers(L_CRIT, "OPM: got a bad listener: %s:%s", parv[0], parv[1]);
+		exit(EX_PROVIDER_ERROR);
+	}
+
+#ifdef RB_IPV6
+	if(GET_SS_FAMILY(&addr) == AF_INET6)
+		listener = &listeners[LISTEN_IPV6];
+	else
+#endif
+		listener = &listeners[LISTEN_IPV4];
+
+	if(strcmp(listener->ip, parv[0]) == 0 || listener->port == port)
+		return;
+
+	if((F = rb_socket(GET_SS_FAMILY(&addr), SOCK_STREAM, 0, "OPM listener socket")) == NULL)
+	{
+		/* This shouldn't fail, or we have problems... */
+		warn_opers(L_CRIT, "OPM: cannot create socket: %s", strerror(errno));
+		exit(EX_PROVIDER_ERROR);
+	}
+
+	if(setsockopt(rb_get_fd(F), SOL_SOCKET, SO_REUSEADDR, (char *)&opt, sizeof(opt)))
+	{
+		/* This shouldn't fail either... */
+		warn_opers(L_CRIT, "OPM: cannot set options on socket: %s", strerror(errno));
+		exit(EX_PROVIDER_ERROR);
+	}
+
+	if(bind(rb_get_fd(F), (struct sockaddr *)&addr, GET_SS_LEN(&addr)))
+	{
+		/* Shit happens, let's not cripple authd over this */
+		warn_opers(L_WARN, "OPM: cannot bind on socket: %s", strerror(errno));
+		rb_close(F);
+		return;
+	}
+
+	if(rb_listen(F, SOMAXCONN, false)) /* deferred accept could interfere with detection */
+	{
+		warn_opers(L_WARN, "OPM: cannot listen on socket: %s", strerror(errno));
+		rb_close(F);
+		return;
+	}
+
+	if(listener->F != NULL)
+		/* Close old listener */
+		rb_close(listener->F);
+
+	listener->F = F;
+
+	/* Cancel old clients that may be on old stale listener
+	 * XXX - should rescan clients that need it
+	 */
+	RB_DICTIONARY_FOREACH(auth, &iter, auth_clients)
+	{
+		opm_cancel(auth);
+	}
+
+#ifdef RB_IPV6
+	if(GET_SS_FAMILY(&addr) == AF_INET6)
+		((struct sockaddr_in6 *)&addr)->sin6_port = htons(port);
+	else
+#endif
+		((struct sockaddr_in *)&addr)->sin_port = htons(port);
+
+	/* Copy data */
+	rb_strlcpy(listener->ip, parv[0], sizeof(listener->ip));
+	listener->port = (uint16_t)port;
+	listener->addr = addr;
+
+	opm_enable = true; /* Implicitly set this to true for now if we have a listener */
+	rb_accept_tcp(F, NULL, accept_opm, listener);
+}
+
+struct auth_opts_handler opm_options[] =
+{
+	{ "opm_timeout", 1, add_conf_opm_timeout },
+	{ "opm_enabled", 1, set_opm_enabled },
+	{ "opm_listener", 2, set_opm_listener },
+	{ NULL, 0, NULL },
+};
+
+struct auth_provider opm_provider =
+{
+	.id = PROVIDER_OPM,
+	.destroy = opm_destroy,
+	.start = opm_start,
+	.cancel = opm_cancel,
+	.timeout = opm_cancel,
+	.opt_handlers = opm_options,
+};