diff --git a/include/bitcoin/network/protocols/protocol_address_in_31402.hpp b/include/bitcoin/network/protocols/protocol_address_in_31402.hpp
index 4b871607f..40e39e88c 100644
--- a/include/bitcoin/network/protocols/protocol_address_in_31402.hpp
+++ b/include/bitcoin/network/protocols/protocol_address_in_31402.hpp
@@ -27,12 +27,11 @@
 #include <bitcoin/network/messages/messages.hpp>
 #include <bitcoin/network/net/net.hpp>
 #include <bitcoin/network/protocols/protocol.hpp>
+#include <bitcoin/network/sessions/sessions.hpp>
 
 namespace libbitcoin {
 namespace network {
 
-class session;
-
 class BCT_API protocol_address_in_31402
   : public protocol, protected tracker<protocol_address_in_31402>
 {
diff --git a/include/bitcoin/network/protocols/protocol_address_out_31402.hpp b/include/bitcoin/network/protocols/protocol_address_out_31402.hpp
index 9eef56697..29326f4fd 100644
--- a/include/bitcoin/network/protocols/protocol_address_out_31402.hpp
+++ b/include/bitcoin/network/protocols/protocol_address_out_31402.hpp
@@ -27,12 +27,11 @@
 #include <bitcoin/network/messages/messages.hpp>
 #include <bitcoin/network/net/net.hpp>
 #include <bitcoin/network/protocols/protocol.hpp>
+#include <bitcoin/network/sessions/sessions.hpp>
 
 namespace libbitcoin {
 namespace network {
 
-class session;
-
 class BCT_API protocol_address_out_31402
   : public protocol, protected tracker<protocol_address_out_31402>
 {
diff --git a/include/bitcoin/network/protocols/protocol_alert_31402.hpp b/include/bitcoin/network/protocols/protocol_alert_31402.hpp
index 94a4af2fb..1b6728e68 100644
--- a/include/bitcoin/network/protocols/protocol_alert_31402.hpp
+++ b/include/bitcoin/network/protocols/protocol_alert_31402.hpp
@@ -27,12 +27,11 @@
 #include <bitcoin/network/messages/messages.hpp>
 #include <bitcoin/network/net/net.hpp>
 #include <bitcoin/network/protocols/protocol.hpp>
+#include <bitcoin/network/sessions/sessions.hpp>
 
 namespace libbitcoin {
 namespace network {
 
-class session;
-
 class BCT_API protocol_alert_31402
   : public protocol, protected tracker<protocol_alert_31402>
 {
diff --git a/include/bitcoin/network/protocols/protocol_ping_31402.hpp b/include/bitcoin/network/protocols/protocol_ping_31402.hpp
index 6b15539a9..485b0360e 100644
--- a/include/bitcoin/network/protocols/protocol_ping_31402.hpp
+++ b/include/bitcoin/network/protocols/protocol_ping_31402.hpp
@@ -27,12 +27,11 @@
 #include <bitcoin/network/messages/messages.hpp>
 #include <bitcoin/network/net/net.hpp>
 #include <bitcoin/network/protocols/protocol.hpp>
+#include <bitcoin/network/sessions/sessions.hpp>
 
 namespace libbitcoin {
 namespace network {
 
-class session;
-
 class BCT_API protocol_ping_31402
   : public protocol, protected tracker<protocol_ping_31402>
 {
diff --git a/include/bitcoin/network/protocols/protocol_ping_60001.hpp b/include/bitcoin/network/protocols/protocol_ping_60001.hpp
index 55fa78fc0..926fe21d3 100644
--- a/include/bitcoin/network/protocols/protocol_ping_60001.hpp
+++ b/include/bitcoin/network/protocols/protocol_ping_60001.hpp
@@ -27,12 +27,11 @@
 #include <bitcoin/network/messages/messages.hpp>
 #include <bitcoin/network/net/net.hpp>
 #include <bitcoin/network/protocols/protocol_ping_31402.hpp>
+#include <bitcoin/network/sessions/sessions.hpp>
 
 namespace libbitcoin {
 namespace network {
 
-class session;
-
 class BCT_API protocol_ping_60001
   : public protocol_ping_31402, protected tracker<protocol_ping_60001>
 {
diff --git a/include/bitcoin/network/protocols/protocol_reject_70002.hpp b/include/bitcoin/network/protocols/protocol_reject_70002.hpp
index d0fb07c52..995e4f855 100644
--- a/include/bitcoin/network/protocols/protocol_reject_70002.hpp
+++ b/include/bitcoin/network/protocols/protocol_reject_70002.hpp
@@ -27,12 +27,11 @@
 #include <bitcoin/network/messages/messages.hpp>
 #include <bitcoin/network/net/net.hpp>
 #include <bitcoin/network/protocols/protocol.hpp>
+#include <bitcoin/network/sessions/sessions.hpp>
 
 namespace libbitcoin {
 namespace network {
 
-class session;
-
 class BCT_API protocol_reject_70002
   : public protocol, protected tracker<protocol_reject_70002>
 {
diff --git a/include/bitcoin/network/protocols/protocol_seed_31402.hpp b/include/bitcoin/network/protocols/protocol_seed_31402.hpp
index dbd42c561..5eb511a53 100644
--- a/include/bitcoin/network/protocols/protocol_seed_31402.hpp
+++ b/include/bitcoin/network/protocols/protocol_seed_31402.hpp
@@ -27,12 +27,10 @@
 #include <bitcoin/network/messages/messages.hpp>
 #include <bitcoin/network/net/net.hpp>
 #include <bitcoin/network/protocols/protocol.hpp>
+#include <bitcoin/network/sessions/sessions.hpp>
 
 namespace libbitcoin {
 namespace network {
-
-class session;
-
 class BCT_API protocol_seed_31402
   : public protocol, protected tracker<protocol_seed_31402>
 {
diff --git a/include/bitcoin/network/protocols/protocol_version_31402.hpp b/include/bitcoin/network/protocols/protocol_version_31402.hpp
index a62f3c878..542223c20 100644
--- a/include/bitcoin/network/protocols/protocol_version_31402.hpp
+++ b/include/bitcoin/network/protocols/protocol_version_31402.hpp
@@ -27,12 +27,11 @@
 #include <bitcoin/network/messages/messages.hpp>
 #include <bitcoin/network/net/net.hpp>
 #include <bitcoin/network/protocols/protocol.hpp>
+#include <bitcoin/network/sessions/sessions.hpp>
 
 namespace libbitcoin {
 namespace network {
 
-class session;
-
 class BCT_API protocol_version_31402
   : public protocol, protected tracker<protocol_version_31402>
 {
diff --git a/include/bitcoin/network/protocols/protocol_version_70001.hpp b/include/bitcoin/network/protocols/protocol_version_70001.hpp
index 18a29eea7..bab1d1c3c 100644
--- a/include/bitcoin/network/protocols/protocol_version_70001.hpp
+++ b/include/bitcoin/network/protocols/protocol_version_70001.hpp
@@ -27,12 +27,11 @@
 #include <bitcoin/network/messages/messages.hpp>
 #include <bitcoin/network/net/net.hpp>
 #include <bitcoin/network/protocols/protocol_version_31402.hpp>
+#include <bitcoin/network/sessions/sessions.hpp>
 
 namespace libbitcoin {
 namespace network {
 
-class session;
-
 class BCT_API protocol_version_70001
   : public protocol_version_31402, protected tracker<protocol_version_70001>
 {
diff --git a/include/bitcoin/network/protocols/protocol_version_70002.hpp b/include/bitcoin/network/protocols/protocol_version_70002.hpp
index 136ae7cef..cc2055f78 100644
--- a/include/bitcoin/network/protocols/protocol_version_70002.hpp
+++ b/include/bitcoin/network/protocols/protocol_version_70002.hpp
@@ -27,12 +27,11 @@
 #include <bitcoin/network/messages/messages.hpp>
 #include <bitcoin/network/net/net.hpp>
 #include <bitcoin/network/protocols/protocol_version_70001.hpp>
+#include <bitcoin/network/sessions/sessions.hpp>
 
 namespace libbitcoin {
 namespace network {
 
-class session;
-
 class BCT_API protocol_version_70002
   : public protocol_version_70001, protected tracker<protocol_version_70002>
 {