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Barracuda Web Security Gateway

Why does my Barracuda Web Filter have such high latency? How can I fix this?

  • Type: Knowledgebase
  • Date changed: 3 years ago
Solution #00003562

All Barracuda Web Filters, firmware version 3.3.

The Barracuda Web Filter?s performance can be impacted by a number of environmental factors. The Web Filter's position in the network, unnecessary traffic, a high number of users, a high number of connections, uniformly high internet usage leading to a blow-up of reporting data, firewalls throttling traffic because of IP spoofing, slow DNS lookup times, and other problems can all contribute to latency.

Our latest firmware releases have a significantly expanded feature set that now includes advanced reporting, custom Content Filtering categories, expanded application filtering, and SSL filtering amongst many other enhancements. A small number of customers who may have been at the upper limit of their Barracuda Web Filter (in terms of concurrent users or connections) on older firmware releases may see latency issues after the upgrade.

The first step in addressing this issue should be to isolate the reason for the latency, and then Barracuda Networks Technical Support can recommend the best course of action.

To help identify the root cause, Barracuda Networks Technical Support may set up a diagnostic utility that will periodically monitor the load on the box, noting the number of connections, users, DNS lookups, and so on at various points throughout the day. This can help identify occasional bursts in activity or network delays that can contribute to latency.

Some additional diagnostic steps may include temporarily exempting some network portions and / or turning off reporting for a short while. Exempting users by IP may help identify unnecessary traffic and also check if the latency is related to the load on the Barracuda Web Filter. Reporting is one of the more resource-consuming activities of the Barracuda Web Filter, so turning off reporting can help identify if the problem is related to the reporting engine.

The process of diagnosis can take up to a day, but this approach enables Barracuda Networks technical Support to provide a targeted long-term solution, rather than a bunch of ad-hoc steps.

Additional Notes:
From the Barracuda Web Filter BASIC > Status page in the web interface, you can monitor performance metrics including System Load, Storage Usage, and Number of TCP Connections in real-time. These metrics are discussed in the online help for the BASIC > Status page. If the system exceeds system load thresholds and you have previously enabled Safe mode, the Barracuda Web Filter will pass traffic through without filtering - rather than blocking Internet access. Please see the online administrator guide at for more intormation.

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