On Tue, 15 Feb 2005, Jay Hennigan wrote:
Vonage devices initiate an outbound TFTP connection back to Vonage to snarf their configs on initial connection and also (presumably) on reboot.
Many, many VoIP devices do this, including Cisco phones in all major flavors. If an ISP is blocking TFTP originated by its customers at the border, this will cause numerous problems with many VoIP devices as well as numerous other things where a customer needs to initiate a TFTP session over the Internet.
Filtering customer-initiated TFTP will cause problems with many legitimate applications and devices.
Most devices have moved to http config, sipura, snom, panasonic, etc. We moved away from tftp because of a lot of NAT and blocking issues. As far as SIP, I don't see it as a major problem since you can use any port.
<> Nathan Stratton BroadVoice, Inc. nathan at robotics.net Talk IS Cheap http://www.robotics.net http://www.broadvoice.com