Troubleshooting Low Interface Throughput

Configuration guides, troubleshooting and practical advice for AZTCOFW.

Articles

8 results

Client/Testing Method

The slowness may not be from any cause on the firewall. It could be the client itself or how it connects. Testing a 100Mbit/s WAN over 802.11g wireless, for example, would never show full speed. Testing a 300Mbit/s WAN f

Duplex Mismatch

A duplex mismatch is also possible, though this is more common on circuits 100Mbit/s or less. Some providers are stuck in the stone age and still insist on hard-coding ports on CPEs such as fiber converters at 100Mbit/s

Hardware/Driver Tuning Required

If a CPU core is fully utilized by interrupts, the network card driver may need tuning. Some cards, such as igb, are able to use more queues for processing packets which will spread the load across multiple cores and res

Insufficient Hardware

The first thing to check is that the hardware is capable of pushing the expected amount of traffic. In some cases this is more obvious, such as a newer multi-core server being unable to transfer small amounts of packets,

ISP Issues

If every other factor has been eliminated, test the modem without the firewall involved. If the speed is still low, it may be the ISP to blame, or the Modem/CPE.

MTU Issues

Issues with upload speed frequently end up being issues with the MTU. If the MTU on AZTCO-FW software (default 1500), is higher than the MTU of the upstream link, it can result in packets being fragmented, lost, or other

Traffic Shaping

If the traffic shaping wizard was run previously before an increase in upstream bandwidth, the old limits may still be in effect. Visit Firewall > Traffic Shaper and check the root interface queues, and qInternet queues

WAN Connection

There could also be issues between the WAN and the Modem/CPE. It could be a cable, or a quirk in how the two interfaces talk to each other. Place a small switch between the firewall and the Modem/CPE as a test.