diff --git a/setup.md b/setup.md
index dad2d41..6c3757c 100644
--- a/setup.md
+++ b/setup.md
@@ -106,10 +106,11 @@ To be able to use multiple IP addresses on a host to create multiple *subflows*
 
 {: .info}
 > A server having only one network interface does not need to configure anything
-> else: the client will create additional subflows as needed.
+> else: the client will be able to attach additional subflows as needed -- max 2
+> by default, see the [Limits](#limits) section below.
 >
 > It might be interesting to announce additional IPv4/6 addresses. Some clients
-> might be connected to networks having only an IPv4 or an IPv6 address. Also
+> might be connected to networks having only an IPv4 or an IPv6 address. Also,
 > consider that IPv4 and IPv6 packets are often routed differently through some
 > networks, resulting in different latencies.
 
@@ -179,10 +180,19 @@ It is also important to make sure the limits are high enough:
 ip mptcp limits set [ subflows NR ] [ add_addr_accepted NR ]
 ```
 
-`subflows` is the limit of created and accepted subflows (paths), and
-`add_addr_accepted` is the limit of accepted `ADD_ADDR` -- IP address
-notification from the other peer -- that will result in the creation of
-subflows.
+- `subflows` is the limit of additional created and accepted subflows (paths),
+  for both the client and server sides (default is 2).
+- `add_addr_accepted` is the limit of accepted `ADD_ADDR` -- IP address
+  notification from the other peer -- that will result in the creation of
+  subflows, typically only for the client side (default is 0).
+
+{: .note}
+It is possible to reach the limits with fewer established subflows than
+expected, e.g. when new subflow requests cannot reach the other peer. In case of
+problem, please increase the limits, use `ss -Mai` to check the counters, and
+modify the routing or firewall rules to avoid using certain paths between
+specific IP addresses. For example, in a lab setup with dedicated links use
+specific routes rather than letting the kernel select the default route.
 
 ### Manual routing configuration