F5 11.5.x – Client SSL profile cannot contain more than one set of same certificate/key type

Issue Starting in BIG-IP 11.5.0, you can associate multiple SSL certificate/key pair types with a single SSL profile. This configuration allows the virtual server to accept SSL connections from clients supporting newer cryptographic algorithms (such as ECC), while continuing to accept connections from clients supporting traditional algorithms[1]. However, with this new feature you are cannot … Read more

F5 – Unable to Create Local Account with Remote Auth

Issue When remote authentication is configured it is not possible (out of the box) to configure local user accounts. Other then the default admin and root accounts provided. This is also stated within the TMOS Management Guide for BIG-IP Systems, which says: “Excluding the admin account, the entire set of standard user accounts that you … Read more

Brocade ADX – Multiple Health-checks on a Per Domain Basis

Now lets consider the following scenario. The client has multiple domains. Traffic is going to all domains on HTTP. However, these domains are under a single virtual server and each domain requires a separate health-check. In order to achieve this configuration port-aliasing is used. What is port-aliasing, you may ask ? Within the ADX various … Read more

Brocade ADX – Cookie Persistance based on URI

Introduction Within this article we will show you the steps needed to configure cookie persistence (insert) based on URI. i.e cookie persistence is only performed for a single URI. Cookie Insert When cookie insert persistence is configured the loadbalancer selects a server to the send the traffic to. The server id of the server is … Read more

BIGIP F5 – Changing Parent in SSL Profile Removes Certificate, Key and Chain

Issue When updating the parent profile on a client SSL profile the cert-key-chain settings are inherited from the new parent profile. Even though the cert-key-chain is explicitly configured within the child profile. Consider the following, You have a client SSL profile ‘CLIENTSSL’ with the cert, key and chain configured along with a parent profile set … Read more

BIGIP – AAM (Application Acceleration Manager)

What is AAM ? BIGIPs AAM (Application Acceleration Manager) is a set of modules used to optimize web traffic. The modules include : Web Optimization WAN Optimization Profiles – this includes profiles used to deploy various optimization techniques such as SPDY, HTTP compression, OneConnect etc. Bandwidth Controller Rate Shaping Core vs Full AAM comes in … Read more

BIGIP – Advanced Firewall Manager (AFM)

What is AFM ? Introduced within 11.3, AFM (Advanced Firewall Manager) is a licensed module for the BIGIP appliance that provides stateful firewalling along with reporting and DoS protection. Within this article we will look at AFMs key components and also how it processes traffic. Contexts A context defines the scope of a firewall rule. … Read more

BIGIP F5 – How to check the Serial Cable via TMSH/Bigpipe

Within this article we will show you the commands to show the status of the serial cable i.e whether it is connected without the need to physically check the device. Commands The follow commands shows the status that the failover daemon detects on the serial cable from its failover peer. Version Command 10.x b failover … Read more

GTM – Healthcheck Monitor Connections not being Established

Issue You may observe GTM Monitors failing with a message of ‘state: timeout’ within the logs messages. On further investigation you find that though the GTM is trying to build the connection (i.e sending the SYN), there is no response (SYN-ACK) from the destination. Resulting in the probe attempt failing. Reason The reason for this … Read more

Mitigating Poodle on the Brocade ADX

In order to mitigate the Poodle vulnerability on the Brocade ADX SSLv3 must be disabled. However this can only be achieved via the code release 12.4s, which disables SSLv3 completely. All code versions prior to this do not have any method or option to disable the SSLv3 protocol. HealthChecks On the ADX there are 2 … Read more

F5 BIG-IP – Upgrading v10 to v11

Within this article we will provide you with the steps to upgrade an F5 LTM v10 box to v11. New Device Upgrade Below are the steps if you are going to be upgrading your v10 configuration onto a new device. These steps presume that you already have v11 running on your new device. Verify your … Read more

Brocade ADX – What are the healthcheck timeout thresholds ?

What are the Timeout threasholds for Healthchecks on a Brocade ADX ? Check  Timeout Details  L3 (ICMP) 2 sec interval / 4 retries None L4 5 sec interval / 3 retries L4 periodric healtchecks are not enabled by default. L7 5 sec interval / 3 retries None      

The iRule Cookbook

This cookbook is a collection of iRule tips, hints and solutions that I have discovered and found whilst writing and designing iRules across the years. Contents How do I split a URL and assign them to separate variables ? How do I perform DNS Lookups ? What is the easiest way to Rewrite the uri … Read more

BigIP F5 LTM – High Availability / DSC (v11.x)

One of the new features, within v11.x of the Traffic Management Operating System (TMOS) is Device Service Clustering (DSC). Over the previous HA (High Availability) features within v10.x, i.e active-standby, connection mirroring etc., DSC also provides the ability to perform, multi-node clustering, Active-Active (and Active-Standby) setup, greater granularity over which data is synchronized Scope Within … Read more

Brocade ADX – Debug Filters provide Incorrect Timestamps

Issues When exporting a capture from the ADX from a debug filter. The wrong timestamps are written. This results in both the time and date being incorrect when viewing them within a 3rd Party tool (such as Wireshark). However when viewing the packets via an ASCII dump within the debug filter the correct timestamps are … Read more

Why are the GTM monitor connections not establishing ?

Issue You may observe the GTM being unable to successfully establish a TCP connection when initaing a monitor probe to a given destination. Spefically, the GTM will send the SYN, but you notice the destination not responding with the SYN-ACK. There are 2 reasons that can cause this behaviour, Time-Wait Mismatch This occurs when the … Read more

GTM – Why is the monitor marked down after a single failure ?

Issue You may observe the GTM marking the monitor as down even though only a single probe failure has occurred and the timeout not been reached. Reason When configuring a monitor there are various conditions that are considered by the GTM as a down response. This means that the GTM will mark the monitor as … Read more

Brocade ADX – How to tune/configure the TCP stack

Introduction There are 2 main methods for configuring the TCP stack on an ADX, globally or via a tcp profile. Within this article we will look at the main configuration settings available, such as how to configure Nagle, SACK and Window Scaling. TCP Profiles TCP profiles allow you to modify the TCP parameters on a … Read more

Where are Certifcates located within BigIP F5 v11.x ?

Within v11.x of LTM/GTM BigIP certificates are located within a folder called ‘certificate_d’ under the necessary partition folder. i.e /config/filestore/files_d/Common_d/certificate_d By default everything is placed within the common partition folder ‘Common_d’. Below shows an example [email protected]:Active:Standalone] # ls -l /config/filestore/files_d/Common_d/certificate_d total 32 lrwxrwxrwx 1 root root    33 Sep 30 02:52 :Common:ca-bundle.crt_1 -> /config/ssl/ssl.crt/ca-bundle.crt lrwxrwxrwx 1 … Read more

BigIP F5 LTM – Application Visibility and Reporting (aka Analytics)

Summary Introduced within TMOS 11.0, AVR (Application Visibility and Reporting) allows you to gather statistics on the performance of applications, such as pool members, virtual servers etc. From within these statistics, analytics such as latency, response times and throughput (to name but a few) can then be viewed either via either the WebUI or the … Read more

Brocade ADX – The CSW Pseudo Stack

Purpose The purpose of this document is to explain the role and functions of the CSW Pseudo Stack. Summary Within the Brocade ADX feature set is the ability to forward traffic based on layer 7 attributes (such as host header, URI etc.). This is achieved by enabling content switching (CSW). In order for the the … Read more

F5 LTM – What is Auto Last Hop

The auto last hop feature ensures that traffic is sent back via the same hop from which it was sent. This is done by the F5 forwarding traffic to the MAC address of the last hop. The last hop MAC address is recorded within the connection table along with the source and destination addresses.

ADX – What is the order of priority for healthchecks ?

Background The Brocade ADX offers 3 main types of layer 7 healthchecks. These are, Server Healthcheck – Server healthchecks are configured on the real server itself. Once configured it issues a healtcheck to the real server based on the port/protocol configured. Port-Policy – A port-policy is a policy that contains all of your parameters for … Read more

F5 LTM – iRule Variables

The F5 offers a number of different ways to you can represent your data via iRules such as variables, tables, datagroups and arrays. Within this article we will look at the variables. There are 2 main types of variables, local and global. Local Local variables represent data within your local namespace, and are assigned the … Read more

F5 LTM – RAM Cache

Introduction RAM Cache is a feature that provides the ability to serve content to your clients directly from the memory of your F5 appliance. This benefits both client and server by reducing response latency and also server load. What is Cached ? Heres a summary, The following items are cached, All 200, 203, 206, 300, … Read more

Why is the Client Addr field within the UIE persistence record not populated ?

Issue When viewing the UIE persistence records you observe that the Client Addr field is not populated. [email protected](Active)(tmos)# show ltm persistence persist-records all-propertiesSys::Persistent Connectionsuniversal – –———————————————————–TMM           0Mode          universalKey           8ffa6c0012825a76b3b68d10a9c68ad3Age (sec.)    4Virtual Name  VS- Addr Addr Name     POOL- Addr   :: Reason This occurs due to the way in which Client Addr is … Read more

F5 LTM – How to enable TACACS+ Accounting

TACACS+ accounting was first supported within BIG-IP version 10.2.0.  Within this article we will show your the commands required to enable this feature. Configure First of all you will need to enable accounting within your authentication settings (this can be found within the GUI under ‘System / Users / Authentication’) modify sys db config.auditing.forward.destination value … Read more

BIGIP F5 LTM – Action on Service Down

Background “Action on Service Down” defines the action that should be taken once the pool member has been marked as “down” by the associated healthcheck, after it has been selected as the load balancing target for a connection. Configuration To configure “Action on Service Down” goto the GUI and then to ‘Local Traffic / Pools’. … Read more

Brocade ADX – The Dynamic Weighted Predictor

The ADX provides a number of loadbalancing methods (also known as predictors) such as round robin and least connections.Within this article we will look at the Dynamic Weighted loadbalancing method. Summary The Dynamic Weighted balancing method is a dynamic predictor that allows you to distribute traffic based upon the resource usage of your server (such … Read more

F5 LTM – Cookie Persistence between HTTP and HTTPS

BACKGROUND In order to to maintain persistence between services (such as HTTP and HTTPS) on a single Virtual Server two persistence methods are available ; Cookie Hashing and Source IP. In order to perform “true” Cookie (insert) persistence across services an iRule is required. Note : Though cookie persistence (insert) can be performed within the … Read more

Brocade ADX – The keepalive command

Within this article we will look into the ‘keepalive’ command. As this command isn’t greatly documented I thought this would be a good opportunity to explain in a little more detail how it works. Keepalive vs Keep-alive First of all it is worth noting that the ‘keepalive’ command (which is configured under the real server) … Read more

F5 LTM – Rate-limiting via iRules

Within this article we look at how to rate-limit traffic via the use of an iRule. iRule The Table Command So that we can rate-limit traffic the iRule command ‘table’ is used. The table command (as the name suggests) provides the ability to create, delete, and append tables, along with being able to define timeouts … Read more

Brocade ADX – SSL Sessions fail when using CSW and Reverse Proxy

Symptoms You may find that when enabling SSL (termination) and a CSW policy your SSL session fails due to the ADX issuing a RST back to the client. When running a url debug via rcon you see the following : URL: process client packet return error CSW_PARSE_ERROR_MAX_MEMORY[80] ???         Free multiple stored packets.         HTTP … Read more

Brocade ADX – HTTP packets dropped when using pipeling and CSW

Symptoms When enabling CSW and running HTTP pipelining you may experience a breakdown in your HTTP session. Issue When enabling CSW on a Virtual Server pipelining is enabled on the designated port by default. The issue occurs when a second GET request comes in before the first GET/POST answer is fully received from the server (this … Read more

BIG-IP F5 LTM – Geolocation

One great feature of the F5 Local Traffic Manager is ability to distribute traffic basic on its geographical location. This feature was introduced within v10.1 thanks to F5`s partnership with Neustar (previously) Quova. The geolocation component uses a (local) IP geolocation database (on the F5) to determine the geographically location of the IP address. To … Read more

Brocade ADX – Policy-Based Server Load Balancing

Policy-Based Server Load Balancing (PB-SLB) provides the ability to distribute traffic based on the source IP address of the client. There are 2 ways in which to configure PB-SLB. You can either pull a list of IP`s from a TFTP server or define the IP`s directly on the ADX.This example is based on defining the … Read more

Brocade ADX – How to Configure SSL/TLS

The Brocade ADX offers 2 ways to configure SSL. These are, SSL (Termination) – Allows for SSL termination at the loadbalancer so that unencrypted traffic can be sent onto the backend servers. This is also known as client side encryption/decryption. SSL Proxy – Allows for the Brocade ADX to decrypt and then re-encrypt the traffic … Read more

F5 LTM – ICMP packet loss when using packet filters

Issue You may observe that ICMP response (return) traffic is randomly dropped by the F5. This behaviour occurs when using tagged VLANs and packet-filters on the F5.Below shows the issue in further detail. An ICMP Ping is initiated from the F5 and a packet capture is run.  We can see from the Ping that the … Read more

F5 LTM – SNMP Error “No object identifier specified in context”

When trying to view your SNMP configuration from within the Web UI you may observe the following error: No object identifier specified in context Solution To resolve this remove the community via bigpipe and save. You will then notice that the SNMP community has been removed via the Web UI. This can then be re-added … Read more

Brocade ADX – Packet Capture

The Brocade ADX provides the ability to capture network traffic which can then be viewed later for further analysis. This is achieved via the  debug filter.Within this article we will provide the necessary steps required to configure, run, save and then export a debug filter. Debug Filter Mode First of all we enter the debug … Read more

Cisco CSS – Deny traffic based on User-Agent header

Within this article we will show you how to deny traffic based on the HTTP User-Agent header. This is achieved by configuring a header-field-group. Within this group we define a header string rule that matches any header that does not contain a defined string. This group is then associated to a content rule. header-field-group deny-agent … Read more

Brocade ADX – High Availability

The Brocade ADX offers 3 types of HA. There are : Sym Active-Standby – Sym Active-Standby is only available on Router code. Both devices receive traffic but only the VIP with the highest sym-priority processes the traffic.Sym Active-Active – Sym Active-Active is only available on Router code. Both devices receive traffic, traffic for each VIP … Read more

Brocade ADX – How do I clear the debug-filter buffer ?

Within this article we will look at the commands required to clear the debug-filter buffer on an ADX Loadbalancer.The command that is used to clear the buffer is “no buffer-size <buffer size>”. Below shows the necessary steps. First of all we place ourselves into the debug filter prompt. We check the amount that we have … Read more

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