diff --git a/sendmail-8.15.2-libmilter-socket-activation.patch b/sendmail-8.15.2-libmilter-socket-activation.patch
new file mode 100644
index 0000000..e8251bc
--- /dev/null
+++ b/sendmail-8.15.2-libmilter-socket-activation.patch
@@ -0,0 +1,80 @@
+Description: systemd-like socket activation support for libmilter
+Author: Mikhail Gusarov <dottedmag@debian.org
+diff --git a/libmilter/docs/smfi_setconn.html b/libmilter/docs/smfi_setconn.html
+index eba7c5b..5b272a0 100644
+--- a/libmilter/docs/smfi_setconn.html
++++ b/libmilter/docs/smfi_setconn.html
+@@ -43,6 +43,7 @@ Set the socket through which this filter should communicate with sendmail.
+ 	<LI><CODE>{unix|local}:/path/to/file</CODE> -- A named pipe.
+ 	<LI><CODE>inet:port@{hostname|ip-address}</CODE> -- An IPV4 socket.
+ 	<LI><CODE>inet6:port@{hostname|ip-address}</CODE> -- An IPV6 socket.
++	<LI><CODE>fd:number</CODE> -- Pre-opened file descriptor.
+ 	</UL>
+ 	</TD></TR>
+     </TABLE>
+diff --git a/libmilter/listener.c b/libmilter/listener.c
+index 11d92bb..2ab533d 100644
+--- a/libmilter/listener.c
++++ b/libmilter/listener.c
+@@ -197,6 +197,11 @@ mi_milteropen(conn, backlog, rmsocket, name)
+ 			L_socksize = sizeof addr.sin6;
+ 		}
+ #endif /* NETINET6 */
++		else if (strcasecmp(p, "fd") == 0)
++		{
++			addr.sa.sa_family = AF_UNSPEC;
++			L_socksize = sizeof (_SOCK_ADDR);
++		}
+ 		else
+ 		{
+ 			smi_log(SMI_LOG_ERR, "%s: unknown socket type %s",
+@@ -443,7 +448,21 @@ mi_milteropen(conn, backlog, rmsocket, name)
+ 	}
+ #endif /* NETINET || NETINET6 */
+ 
+-	sock = socket(addr.sa.sa_family, SOCK_STREAM, 0);
++	if (addr.sa.sa_family == AF_UNSPEC)
++	{
++		char *end;
++		sock = strtol(colon, &end, 10);
++		if (*end != '\0' || sock < 0)
++		{
++			smi_log(SMI_LOG_ERR, "%s: expected positive integer as fd, got %s", name, colon);
++			return INVALID_SOCKET;
++		}
++	}
++	else
++	{
++		sock = socket(addr.sa.sa_family, SOCK_STREAM, 0);
++	}
++
+ 	if (!ValidSocket(sock))
+ 	{
+ 		smi_log(SMI_LOG_ERR,
+@@ -466,6 +485,7 @@ mi_milteropen(conn, backlog, rmsocket, name)
+ #if NETUNIX
+ 	    addr.sa.sa_family != AF_UNIX &&
+ #endif /* NETUNIX */
++	    addr.sa.sa_family != AF_UNSPEC &&
+ 	    setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *) &sockopt,
+ 		       sizeof(sockopt)) == -1)
+ 	{
+@@ -511,7 +531,8 @@ mi_milteropen(conn, backlog, rmsocket, name)
+ 	}
+ #endif /* NETUNIX */
+ 
+-	if (bind(sock, &addr.sa, L_socksize) < 0)
++	if (addr.sa.sa_family != AF_UNSPEC &&
++	    bind(sock, &addr.sa, L_socksize) < 0)
+ 	{
+ 		smi_log(SMI_LOG_ERR,
+ 			"%s: Unable to bind to port %s: %s",
+@@ -818,7 +839,7 @@ mi_listener(conn, dbg, smfi, timeout, backlog)
+ # ifdef BSD4_4_SOCKADDR
+ 		     cliaddr.sa.sa_len == 0 ||
+ # endif /* BSD4_4_SOCKADDR */
+-		     cliaddr.sa.sa_family != L_family))
++		     (L_family != AF_UNSPEC && cliaddr.sa.sa_family != L_family)))
+ 		{
+ 			(void) closesocket(connfd);
+ 			connfd = INVALID_SOCKET;
diff --git a/sendmail.spec b/sendmail.spec
index c857189..85087c8 100644
--- a/sendmail.spec
+++ b/sendmail.spec
@@ -21,7 +21,7 @@
 Summary: A widely used Mail Transport Agent (MTA)
 Name: sendmail
 Version: 8.15.2
-Release: 2%{?dist}
+Release: 3%{?dist}
 License: Sendmail
 Group: System Environment/Daemons
 URL: http://www.sendmail.org/
@@ -87,6 +87,7 @@ Patch23: sendmail-8.14.8-sasl2-in-etc.patch
 # add QoS support, patch from Philip Prindeville <philipp@fedoraproject.org>
 # upstream reserved option ID 0xe7 for testing of this new feature, #576643
 Patch25: sendmail-8.15.2-qos.patch
+Patch26: sendmail-8.15.2-libmilter-socket-activation.patch
 Buildroot: %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 BuildRequires: tcp_wrappers-devel
 BuildRequires: libdb-devel
@@ -208,6 +209,7 @@ cp devtools/M4/UNIX/{,shared}library.m4
 %patch18 -p1 -b .switchfile
 %patch23 -p1 -b .sasl2-in-etc
 %patch25 -p1 -b .qos
+%patch26 -p1 -b .libmilter-socket-activation
 
 for f in RELEASE_NOTES contrib/etrn.0; do
 	iconv -f iso8859-1 -t utf8 -o ${f}{_,} &&
@@ -701,6 +703,10 @@ fi
 %endif
 
 %changelog
+* Wed Sep 23 2015 Jaroslav Škarvada <jskarvad@redhat.com> - 8.15.2-3
+- Added support for socket activation to libmilter
+  Resolves: rhbz#1262535
+
 * Wed Jul 22 2015 Lubomir Rintel <lkundrak@v3.sk> - 8.15.2-2
 - nm-dispacher: don't block the connection activation
   Resolves: rhbz#1237070