Proxy Server FAQ

Sambar Server Documentation

Proxy Server FAQs

The Sambar Server includes a simple proxy server that can be configured to run as part of the Sambar Server. A proxy server allows one computer to communicate with the internet on behalf of other computers, allowing a single Internet connection to be shared by any number of machines simultaneously.

The proxy features of the Sambar Server are configured OFF by default, and must be turned on using the administration pages which provide for proxy configuration.

Why would I use a proxy server rather than a router ?

Routers can only be used when every machine on the network has a public IP address. The costs associated with maintaining your own class C network are significantly higher than having single dial-up or ISDN connection.

What protocols are supported by the Sambar Proxy Server ?

HTTP
SSL Tunneling (security proxy)
SMTP, POP3 and IMAP4
Native FTP proxy (via user@host)
NNTP
Bridge proxy (any TCP-based client-server connection)
FTP tunneling over HTTP (browser-based ftp://<username>:<password>@<server-name> requests)

Can I used the Sambar Proxy Server with ISDN ?

Yes. The Sambar Proxy Server should operate over any TCP/IP connection.

Does the Sambar Proxy Server support IP security ?

Yes. The config/security.ini file can be used to setup IP-based security filtering. The [proxyaccept] section should be configured with the IP address string matching the clients on your private network. Leaving the default [proxyaccept] entry (*) allows anyone on the internet access to your private network via the proxy server.

Can POP3 clients connect to mail servers other than the one configured in the Sambar Server ?

Yes. If the POP3 Enhanced mode is enabled, the Sambar Server POP3 proxy will attempt to interpret the username and extract an alternate POP3 server to connect to from the name specified. See the Proxy documentation for more details on usage.

How should I configure the clients on my private network?

RFC 1918 specifies the IP addresses and netmasks suitable for private networks. The following three blocks of the IP address space are reserved for private internets:

10.0.0.0 - 10.255.255.255 (10/8 prefix)
172.16.0.0 - 172.31.255.255 (172.16/12 prefix)
192.168.0.0 - 192.168.255.255 (192.168/16 prefix)

Note: The above is all the free networking/system management support available from Sambar Technologies.

Should I use the HTTP/1.1 Advanced proxy functionality in IE ?

No. The proxy in the Sambar Server are "pass-thru" proxies that do as little interpretation of the protocol being relayed as possible. For HTTP requests, only the initial header request is evaluated to determine the remote site to pass the request to; subsequent requests are passed uninterpreted.

That said, the Microsoft's Internet Explorer "use HTTP/1.1 over Proxy" feature seems to expect additional HTTP header information when passing via a proxy. Since the Sambar Server does not implement any proxy-specific code, this functionality may result in requests that hang.