Scannex ip.buffer, Manual

Page: 36 / 152

Scannex ip.buffer User Manual
© UK 2007-2021 Scannex Electronics Ltd. All rights reserved worldwide.
Firewalling
When using the “On demand” connection method and when connected to an ISP the
ip.buffer implements a firewall to prevent any TCP/IP connections being made to the
device. It is impossible to gain access to the web server, FTP server, or any other ports
while dialled up to an ISP (even if the ISP is actually a RAS server).
If using the “Nailed-up (permanent)” connect type then the firewall is disabled. This
allows remote management of the ip.buffers within a VPN network (e.g. through a
specialised SIM contract).
DNS Servers
Normally, for Ethernet LAN connections, the ip.buffer will use the DNS1 and DNS2
addresses programmed in the Network & System web page. However, for delivery
destinations that use the modem the DNS requests are sent across the PPP modem link
using the DNS server addresses supplied at connection by the remote PPP end
20 .
If the remote machine name is already in the DNS cache (whether obtained via the LAN or
the modem) the cache entry is used.
20 While the PPP link is active, the LAN DNS server addresses are still used for Ethernet LAN
transfers.
Page 32
Scannex ip.buffer User Manual
© UK 2007-2021 Scannex Electronics Ltd. All rights reserved worldwide.
Firewalling
When using the “On demand” connection method and when connected to an ISP the
ip.buffer implements a firewall to prevent any TCP/IP connections being made to the
device. It is impossible to gain access to the web server, FTP server, or any other ports
while dialled up to an ISP (even if the ISP is actually a RAS server).
If using the “Nailed-up (permanent)” connect type then the firewall is disabled. This
allows remote management of the ip.buffers within a VPN network (e.g. through a
specialised SIM contract).
DNS Servers
Normally, for Ethernet LAN connections, the ip.buffer will use the DNS1 and DNS2
addresses programmed in the Network & System web page. However, for delivery
destinations that use the modem the DNS requests are sent across the PPP modem link
using the DNS server addresses supplied at connection by the remote PPP end
20 .
If the remote machine name is already in the DNS cache (whether obtained via the LAN or
the modem) the cache entry is used.
20 While the PPP link is active, the LAN DNS server addresses are still used for Ethernet LAN
transfers.
Page 32