diff --git a/src/lib-http/test-http-client-errors.c b/src/lib-http/test-http-client-errors.c
index 3ccc6b504d..1b8d80c418 100644
--- a/src/lib-http/test-http-client-errors.c
+++ b/src/lib-http/test-http-client-errors.c
@@ -2988,7 +2988,7 @@ server_connection_init(int fd)
 
 	net_set_nonblock(fd, TRUE);
 
-	pool = pool_alloconly_create("server connection", 256);
+	pool = pool_alloconly_create("server connection", 512);
 	conn = p_new(pool, struct server_connection, 1);
 	conn->pool = pool;
 
diff --git a/src/lib-smtp/smtp-client-connection.c b/src/lib-smtp/smtp-client-connection.c
index c5ceabe8ce..bbb67e2a1a 100644
--- a/src/lib-smtp/smtp-client-connection.c
+++ b/src/lib-smtp/smtp-client-connection.c
@@ -1622,7 +1622,7 @@ smtp_client_connection_create(struct smtp_client *client,
 	struct smtp_client_connection *conn;
 	pool_t pool;
 
-	pool = pool_alloconly_create("smtp client connection", 512);
+	pool = pool_alloconly_create("smtp client connection", 2048);
 	conn = p_new(pool, struct smtp_client_connection, 1);
 	conn->refcount = 1;
 	conn->pool = pool;
diff --git a/src/lib-smtp/smtp-client-transaction.c b/src/lib-smtp/smtp-client-transaction.c
index dc78e6a15a..6cf8c9a8e2 100644
--- a/src/lib-smtp/smtp-client-transaction.c
+++ b/src/lib-smtp/smtp-client-transaction.c
@@ -45,7 +45,7 @@ smtp_client_transaction_rcpt_new(
 	struct smtp_client_transaction_rcpt *rcpt;
 	pool_t pool;
 
-	pool = pool_alloconly_create("smtp transaction rcpt", 256);
+	pool = pool_alloconly_create("smtp transaction rcpt", 512);
 	rcpt = p_new(pool, struct smtp_client_transaction_rcpt, 1);
 	rcpt->pool = pool;
 	rcpt->trans = trans;
@@ -163,7 +163,7 @@ smtp_client_transaction_create(struct smtp_client_connection *conn,
 	struct smtp_client_transaction *trans;
 	pool_t pool;
 
-	pool = pool_alloconly_create("smtp transaction", 512);
+	pool = pool_alloconly_create("smtp transaction", 4096);
 	trans = p_new(pool, struct smtp_client_transaction, 1);
 	trans->refcount = 1;
 	trans->pool = pool;
diff --git a/src/lib-smtp/smtp-reply-parser.c b/src/lib-smtp/smtp-reply-parser.c
index 78cf947fbc..d47eab4513 100644
--- a/src/lib-smtp/smtp-reply-parser.c
+++ b/src/lib-smtp/smtp-reply-parser.c
@@ -146,7 +146,7 @@ smtp_reply_parser_restart(struct smtp_reply_parser *parser)
 	pool_unref(&parser->reply_pool);
 	i_zero(&parser->state);
 
-	parser->reply_pool = pool_alloconly_create("smtp_reply", 256);
+	parser->reply_pool = pool_alloconly_create("smtp_reply", 1024);
 	parser->state.reply = p_new(parser->reply_pool, struct smtp_reply, 1);
 	p_array_init(&parser->state.reply_lines, parser->reply_pool, 8);
 
diff --git a/src/lib-smtp/smtp-server-command.c b/src/lib-smtp/smtp-server-command.c
index 915dc0787c..cdc7b1b5b3 100644
--- a/src/lib-smtp/smtp-server-command.c
+++ b/src/lib-smtp/smtp-server-command.c
@@ -154,7 +154,7 @@ smtp_server_command_alloc(struct smtp_server_connection *conn)
 	struct smtp_server_command *cmd;
 	pool_t pool;
 
-	pool = pool_alloconly_create("smtp_server_command", 256);
+	pool = pool_alloconly_create("smtp_server_command", 1024);
 	cmd = p_new(pool, struct smtp_server_command, 1);
 	cmd->context.pool = pool;
 	cmd->context.cmd = cmd;
diff --git a/src/lib-smtp/smtp-server-connection.c b/src/lib-smtp/smtp-server-connection.c
index a6709cdd96..ff705fba58 100644
--- a/src/lib-smtp/smtp-server-connection.c
+++ b/src/lib-smtp/smtp-server-connection.c
@@ -770,7 +770,7 @@ smtp_server_connection_alloc(struct smtp_server *server,
 	struct smtp_server_connection *conn;
 	pool_t pool;
 
-	pool = pool_alloconly_create("smtp server", 512);
+	pool = pool_alloconly_create("smtp server", 1024);
 	conn = p_new(pool, struct smtp_server_connection, 1);
 	conn->pool = pool;
 	conn->refcount = 1;
diff --git a/src/lib-smtp/smtp-server-transaction.c b/src/lib-smtp/smtp-server-transaction.c
index 9c3e6bb3b0..753b355b27 100644
--- a/src/lib-smtp/smtp-server-transaction.c
+++ b/src/lib-smtp/smtp-server-transaction.c
@@ -23,7 +23,7 @@ smtp_server_transaction_create(struct smtp_server_connection *conn,
 	string_t *id;
 
 	/* create new transaction */
-	pool = pool_alloconly_create("smtp server transaction", 512);
+	pool = pool_alloconly_create("smtp server transaction", 4096);
 	trans = p_new(pool, struct smtp_server_transaction, 1);
 	trans->pool = pool;
 	trans->conn = conn;