diff --git a/.gitignore b/.gitignore
index 024fb98..bfe67c4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
+.venv
 /target
 Cargo.lock
 __pycache__
diff --git a/netsim/.envrc b/netsim/.envrc
new file mode 100644
index 0000000..3550a30
--- /dev/null
+++ b/netsim/.envrc
@@ -0,0 +1 @@
+use flake
diff --git a/netsim/flake.lock b/netsim/flake.lock
new file mode 100644
index 0000000..336fc27
--- /dev/null
+++ b/netsim/flake.lock
@@ -0,0 +1,59 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1719223410,
+        "narHash": "sha256-jtIo8xR0Zp4SalIwmD+OdCwHF4l7OU6PD63UUK4ckt4=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "efb39c6052f3ce51587cf19733f5f4e5d515aa13",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs",
+        "utils": "utils"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
+    "utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1710146030,
+        "narHash": "sha256-SZ5L6eA7HJ/nmkzGG7/ISclqe6oZdOZTNoesiInkXPQ=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "b1d9ab70662946ef0850d488da1c9019f3a9752a",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/netsim/flake.nix b/netsim/flake.nix
new file mode 100644
index 0000000..e906632
--- /dev/null
+++ b/netsim/flake.nix
@@ -0,0 +1,49 @@
+{
+  description = "A flake to set up netsim temporary environment";
+
+  inputs = { utils.url = "github:numtide/flake-utils"; };
+  outputs = { self, nixpkgs, utils }:
+    utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+
+        ovsScripts = "${pkgs.openvswitch}/share/openvswitch/scripts";
+
+        pyPkgs = with pkgs.python3Packages; [
+          pyshark
+          drawsvg
+          dpkt
+          humanfriendly
+          mininet-python
+        ];
+
+        netsim = pkgs.writeScriptBin "netsim" ''
+          #!/bin/sh
+
+          echo "Running with PYTHONPATH: $PYTHONPATH"
+          sudo PYTHONPATH=$PYTHONPATH python3 main.py $@
+        '';
+
+      in {
+        devShell = pkgs.mkShell {
+          buildInputs = with pkgs;
+            [ inetutils mininet openvswitch iperf tshark python3 netsim ]
+            ++ pyPkgs;
+
+          shellHook = ''
+            export OVS_DBDIR=$(pwd)
+            sudo ${ovsScripts}/ovs-ctl start \
+              --db-file="$OVS_DBDIR/conf.db" \
+              --system-id=random
+
+            sudo ovs-vsctl show
+
+            cleanup() {
+              sudo ${ovsScripts}/ovs-ctl stop
+              sudo rm $OVS_DBDIR/conf.db
+            }
+            trap cleanup EXIT
+          '';
+        };
+      });
+}
diff --git a/netsim/main.py b/netsim/main.py
index 4042660..c42d7ee 100644
--- a/netsim/main.py
+++ b/netsim/main.py
@@ -15,7 +15,7 @@
 from network import StarTopo
 from process_sniff import run_viz
 
-TIMEOUT = 60 * 5
+TIMEOUT = 20 # 60 * 5
 
 def logs_on_error(nodes, prefix, code=1, message=None):
     node_counts = {}
@@ -151,10 +151,22 @@ def run(nodes, prefix, args, debug=False, visualize=False):
     # CLI(net)
 
     process_errors = []
+    some_error = False
     for i in range(TIMEOUT):
         time.sleep(1)
-        if not any(p.poll() is None for (n, p) in p_short_box):
+        
+        for (node_name, p) in p_short_box:
+            r = p.poll()
+            print('Supervisor(%s): Process still running after %d seconds.' % (node_name, i + 1))
+            if r is not None and r != 0:
+                print('Supervisor(%s): Process finished %s with exit code %d' % (node_name, prefix, r))
+                process_errors.append('Process has failed: %s with exit code: %d for node: %s' % (prefix, r, node_name))
+                some_error = True
+                break
+
+        if not any(p.poll() is None for (_, p) in p_short_box) or some_error:
             break
+            
     for (node_name, p) in p_short_box:
         if integration:
             r = p.poll()
@@ -167,9 +179,9 @@ def run(nodes, prefix, args, debug=False, visualize=False):
             p.terminate()
 
     if process_errors:
+        logs_on_error(nodes, prefix)
         for error in process_errors:
             print(error)
-        logs_on_error(nodes, prefix)
         cleanup_tmp_dirs(temp_dirs)
         raise Exception('Netsim run failed')
 
diff --git a/netsim/setup.sh b/netsim/setup.sh
index 679e2ed..4167326 100755
--- a/netsim/setup.sh
+++ b/netsim/setup.sh
@@ -1,12 +1,12 @@
-sudo apt install mininet
-sudo apt install openvswitch-testcontroller
-sudo apt install iperf
-# sudo apt install wireshark
-sudo apt install tshark
-sudo pip3 install pyshark
-sudo pip3 install drawsvg
-sudo pip3 install dpkt
-sudo pip3 install humanfriendly
+# sudo apt install mininet
+# sudo apt install openvswitch-testcontroller
+# sudo apt install iperf
+# # sudo apt install wireshark
+# sudo apt install tshark
+# pip3 install pyshark
+# pip3 install drawsvg
+# pip3 install dpkt
+# pip3 install humanfriendly
 mkdir -p logs
 mkdir -p report
 mkdir -p data
diff --git a/netsim/sims/repro/iroh.json b/netsim/sims/repro/iroh.json
new file mode 100644
index 0000000..dffbdec
--- /dev/null
+++ b/netsim/sims/repro/iroh.json
@@ -0,0 +1,63 @@
+{
+    "name": "iroh",
+    "cases": [
+        {
+            "name": "2_to_10",
+            "description": "",
+            "nodes": [
+                {
+                    "name": "iroh_srv",
+                    "count": 2,
+                    "cmd": "./bins/iroh start --add data/1G.bin",
+                    "type": "public",
+                    "wait": 10,
+                    "connect": {
+                        "strategy": "none"
+                    },
+                    "param_parser": "iroh_ticket"
+                },
+                {
+                    "name": "iroh_get",
+                    "count": 10,
+                    "cmd": "time ./bins/iroh blob get --start %s --out STDOUT > /dev/null",
+                    "type": "public",
+                    "connect": {
+                        "strategy": "params",
+                        "node": "iroh_srv"
+                    },
+                    "process": "short",
+                    "parser": "iroh_1gb"
+                }
+            ]
+        },
+        {
+            "name": "2_to_10",
+            "description": "",
+            "nodes": [
+                {
+                    "name": "iroh_srv",
+                    "count": 2,
+                    "cmd": "./bins/iroh start --add data/1G.bin",
+                    "type": "public",
+                    "wait": 10,
+                    "connect": {
+                        "strategy": "none"
+                    },
+                    "param_parser": "iroh_ticket"
+                },
+                {
+                    "name": "iroh_get",
+                    "count": 10,
+                    "cmd": "time ./bins/iroh blob get --start %s --out STDOUT > /dev/null",
+                    "type": "public",
+                    "connect": {
+                        "strategy": "params",
+                        "node": "iroh_srv"
+                    },
+                    "process": "short",
+                    "parser": "iroh_1gb"
+                }
+            ]
+        }
+    ]
+}
\ No newline at end of file