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Merge pull request #196823 from AbdullahBell/NetworkWatcherPortal
Quickstart: Diagnose a virtual machine network traffic filter problem using the Azure portal
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articles/network-watcher/diagnose-vm-network-traffic-filtering-problem.md

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author: damendo
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ms.author: damendo
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editor:
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ms.date: 04/20/2018
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ms.date: 05/02/2022
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ms.assetid:
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ms.topic: quickstart
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ms.service: network-watcher
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## Create a VM
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1. Select **+ Create a resource** found on the upper, left corner of the Azure portal.
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2. Select **Compute**, and then select **Windows Server 2016 Datacenter** or a version of **Ubuntu Server**.
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3. Enter, or select, the following information, accept the defaults for the remaining settings, and then select **OK**:
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1. Select **Compute**, and then select **Windows Server 2019 Datacenter** or a version of **Ubuntu Server**.
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1. Enter, or select, the following information, accept the defaults for the remaining settings, and then select **OK**:
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|Setting|Value|
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|---|---|
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|Name|myVm|
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|User name| Enter a user name of your choosing.|
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|Password| Enter a password of your choosing. The password must be at least 12 characters long and meet the defined complexity requirements.|
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|Subscription| Select your subscription.|
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|Resource group| Select **Create new** and enter **myResourceGroup**.|
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|Location| Select **East US**|
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|Virtual machine name|myVm|
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|Region| Select **East US**|
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|User name| Enter a user name of your choosing.|
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|Password| Enter a password of your choosing. The password must be at least 12 characters long and meet the defined complexity requirements.|
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4. Select a size for the VM and then select **Select**.
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5. Under **Settings**, accept all the defaults, and select **OK**.
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6. Under **Create** of the **Summary**, select **Create** to start VM deployment. The VM takes a few minutes to deploy. Wait for the VM to finish deploying before continuing with the remaining steps.
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1. Select **Review + create** to start VM deployment. The VM takes a few minutes to deploy. Wait for the VM to finish deploying before continuing with the remaining steps.
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## Test network communication
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If you already have a network watcher enabled in at least one region, skip to the [Use IP flow verify](#use-ip-flow-verify).
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1. In the portal, select **All services**. In the **Filter box**, enter *Network Watcher*. When **Network Watcher** appears in the results, select it.
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2. Enable a network watcher in the East US region, because that's the region the VM was deployed to in a previous step. Select **Regions**, to expand it, and then select **...** to the right of **East US**, as shown in the following picture:
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![Enable Network Watcher](./media/diagnose-vm-network-traffic-filtering-problem/enable-network-watcher.png)
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3. Select **Enable Network Watcher**.
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1. In the **Home** portal, select **More services**. In the **Filter box**, enter *Network Watcher*. When **Network Watcher** appears in the results, select it.
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1. Enable a network watcher in the East US region, because that's the region the VM was deployed to in a previous step. Select **Add**, to expand it, and then select **Region** under **Subscription**, as shown in the following picture:
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:::image type="content" source="./media/diagnose-vm-network-traffic-filtering-problem/enable-network-watcher.png" alt-text="Screenshot of how to Enable Network Watcher.":::
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1. Select your region then select **Add**.
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### Use IP flow verify
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When you create a VM, Azure allows and denies network traffic to and from the VM, by default. You might later override Azure's defaults, allowing or denying additional types of traffic.
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1. In the portal, select **All services**. In the **All services** *Filter* box, enter *Network Watcher*. When **Network Watcher** appears in the results, select it.
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2. Select **IP flow verify**, under **NETWORK DIAGNOSTIC TOOLS**.
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3. Select your subscription, enter or select the following values, and then select **Check**, as shown in the picture that follows:
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1. In the **Home** portal, select **More services**. In the **All services** *Filter* box, enter *Network Watcher*. When **Network Watcher** appears in the results, select it.
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1. Select **IP flow verify**, under **Network diagnostic tools**.
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1. Select your subscription, enter or select the following values, and then select **Check**, as shown in the picture that follows:
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|Setting |Value |
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|--------- |--------- |
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| Resource group | Select myResourceGroup |
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| Virtual machine | Select myVm |
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| Subscription | Select your subscription |
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| Resource group | Select **myResourceGroup** |
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| Virtual machine | Select **myVm** |
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| Network interface | myvm - The name of the network interface the portal created when you created the VM is different. |
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| Protocol | TCP |
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| Direction | Outbound |
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| Remote IP address | 13.107.21.200 - One of the addresses for <www.bing.com>. |
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| Remote port | 80 |
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![IP flow verify](./media/diagnose-vm-network-traffic-filtering-problem/ip-flow-verify-outbound.png)
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:::image type="content" source="./media/diagnose-vm-network-traffic-filtering-problem/ip-flow-verify-outbound.png" alt-text="Screenshot of values to input in IP flow verify.":::
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After a few seconds, the result returned informs you that access is allowed because of a security rule named **AllowInternetOutbound**. When you ran the check, Network Watcher automatically created a network watcher in the East US region, if you had an existing network watcher in a region other than the East US region before you ran the check.
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4. Complete step 3 again, but change the **Remote IP address** to **172.31.0.100**. The result returned informs you that access is denied because of a security rule named **DefaultOutboundDenyAll**.
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5. Complete step 3 again, but change the **Direction** to **Inbound**, the **Local port** to **80** and the **Remote port** to **60000**. The result returned informs you that access is denied because of a security rule named **DefaultInboundDenyAll**.
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1. Complete step 3 again, but change the **Remote IP address** to **172.31.0.100**. The result returned informs you that access is denied because of a security rule named **DenyAllOutBound**.
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1. Complete step 3 again, but change the **Direction** to **Inbound**, the **Local port** to **80** and the **Remote port** to **60000**. **Remote IP address** remains **172.31.0.100**. The result returned informs you that access is denied because of a security rule named **DenyAllInBound**.
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Now that you know which security rules are allowing or denying traffic to or from a VM, you can determine how to resolve the problems.
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## View details of a security rule
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1. To determine why the rules in steps 3-5 of **Use IP flow verify** allow or deny communication, review the effective security rules for the network interface in the VM. In the search box at the top of the portal, enter *myvm*. When the **myvm** (or whatever the name of your network interface is) network interface appears in the search results, select it.
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2. Select **Effective security rules** under **SUPPORT + TROUBLESHOOTING**, as shown in the following picture:
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To determine why the rules in steps 3-5 of **Use IP flow verify** allow or deny communication, review the effective security rules for the network interface in the VM.
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![Effective security rules](./media/diagnose-vm-network-traffic-filtering-problem/effective-security-rules.png)
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1. In the search box at the top of the portal, enter *myvm*. When the **myvm Regular Network Interface** appears in the search results, select it.
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1. Select **Effective security rules** under **Support + troubleshooting**, as shown in the following picture:
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:::image type="content" source="./media/diagnose-vm-network-traffic-filtering-problem/effective-security-rules.png" alt-text="Screenshot of Effective security rules.":::
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In step 3 of **Use IP flow verify**, you learned that the reason the communication was allowed is because of the **AllowInternetOutbound** rule. You can see in the previous picture that the **DESTINATION** for the rule is **Internet**. It's not clear how 13.107.21.200, the address you tested in step 3 of **Use IP flow verify**, relates to **Internet** though.
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3. Select the **AllowInternetOutBound** rule, and then select **Destination**, as shown in the following picture:
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In step 3 of **Use IP flow verify**, you learned that the reason the communication was allowed is because of the **AllowInternetOutbound** rule. You can see in the previous picture that the **Destination** for the rule is **Internet**. It's not clear how 13.107.21.200, the address you tested in step 3 of **Use IP flow verify**, relates to **Internet** though.
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1. Select the **AllowInternetOutBound** rule, and then scroll down to **Destination**, as shown in the following picture:
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:::image type="content" source="./media/diagnose-vm-network-traffic-filtering-problem/security-rule-prefixes.png" alt-text="Screenshot of Security rule prefixes.":::
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![Security rule prefixes](./media/diagnose-vm-network-traffic-filtering-problem/security-rule-prefixes.png)
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One of the prefixes in the list is **12.0.0.0/8**, which encompasses the 12.0.0.1-15.255.255.254 range of IP addresses. Since 13.107.21.200 is within that address range, the **AllowInternetOutBound** rule allows the outbound traffic. Additionally, there are no higher priority (lower number) rules shown in the picture in step 2 that override this rule. Close the **Address prefixes** box. To deny outbound communication to 13.107.21.200, you could add a security rule with a higher priority, that denies port 80 outbound to the IP address.
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One of the prefixes in the list is **12.0.0.0/6**, which encompasses the 12.0.0.1-15.255.255.254 range of IP addresses. Since 13.107.21.200 is within that address range, the **AllowInternetOutBound** rule allows the outbound traffic. Additionally, there are no higher priority (lower number) rules shown in the picture in step 2 that override this rule. Close the **Address prefixes** box. To deny outbound communication to 13.107.21.200, you could add a security rule with a higher priority, that denies port 80 outbound to the IP address.
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4. When you ran the outbound check to 172.131.0.100 in step 4 of **Use IP flow verify**, you learned that the **DefaultOutboundDenyAll** rule denied communication. That rule equates to the **DenyAllOutBound** rule shown in the picture in step 2 that specifies **0.0.0.0/0** as the **DESTINATION**. This rule denies the outbound communication to 172.131.0.100, because the address is not within the **DESTINATION** of any of the other **Outbound rules** shown in the picture. To allow the outbound communication, you could add a security rule with a higher priority, that allows outbound traffic to port 80 for the 172.131.0.100 address.
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5. When you ran the inbound check from 172.131.0.100 in step 5 of **Use IP flow verify**, you learned that the **DefaultInboundDenyAll** rule denied communication. That rule equates to the **DenyAllInBound** rule shown in the picture in step 2. The **DenyAllInBound** rule is enforced because no other higher priority rule exists that allows port 80 inbound to the VM from 172.31.0.100. To allow the inbound communication, you could add a security rule with a higher priority, that allows port 80 inbound from 172.31.0.100.
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1. When you ran the outbound check to 172.131.0.100 in step 4 of **Use IP flow verify**, you learned that the **DenyAllOutBound** rule denied communication. That rule equates to the **DenyAllOutBound** rule shown in the picture in step 2 that specifies **0.0.0.0/0** as the **Destination**. This rule denies the outbound communication to 172.131.0.100, because the address is not within the **Destination** of any of the other **Outbound rules** shown in the picture. To allow the outbound communication, you could add a security rule with a higher priority, that allows outbound traffic to port 80 for the 172.131.0.100 address.
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1. When you ran the inbound check from 172.131.0.100 in step 5 of **Use IP flow verify**, you learned that the **DenyAllInBound** rule denied communication. That rule equates to the **DenyAllInBound** rule shown in the picture in step 2. The **DenyAllInBound** rule is enforced because no other higher priority rule exists that allows port 80 inbound to the VM from 172.31.0.100. To allow the inbound communication, you could add a security rule with a higher priority, that allows port 80 inbound from 172.31.0.100.
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The checks in this quickstart tested Azure configuration. If the checks return expected results and you still have network problems, ensure that you don't have a firewall between your VM and the endpoint you're communicating with and that the operating system in your VM doesn't have a firewall that is allowing or denying communication.
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When no longer needed, delete the resource group and all of the resources it contains:
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1. Enter *myResourceGroup* in the **Search** box at the top of the portal. When you see **myResourceGroup** in the search results, select it.
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2. Select **Delete resource group**.
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3. Enter *myResourceGroup* for **TYPE THE RESOURCE GROUP NAME:** and select **Delete**.
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1. Select **Delete resource group**.
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1. Enter *myResourceGroup* for **TYPE THE RESOURCE GROUP NAME:** and select **Delete**.
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## Next steps
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