Slovak versionEnglish version

THR Systems a. s.
Jilemnického 3, Zvolen
tel.: +421 650 52 00 00

Branch Bratislava
THR Systems a. s.

Čapkova 2, Bratislava 1
tel.: +421 650 52 00 15

Branch Nové Zámky
THR Systems a. s.

Turecká 36, Nové Zámky
tel.: +421 650 52 00 33

Solutions - Internet

VoIP Public Branch Exchange

Nowadays the tendency is to use the voice over IP services. It is an amazing choice in the aspect of cost saving. The first there are cost savings by not building separate infrastructure for telephone network. The second the computers could be used as a telephone terminals and it is not required to buy telephones. And finally the costs for internet calls are convenient.

There are more VoIP (Voice over IP) public branche exchanges available for Linux which can serve VoIP services. These exchanges serve many interesting functions, i. e. call routing, call recording, voice menu (IVR), voice mail, call transfer, call listing, music on hold and many others. It is possible to connect the PBX to more providers and therefore save costs. It is possible to connect IP phone to the PBX not only from the local area network, but also from internet. The only requirement for the IP phone is the support of one of the protocols IAX2, SIP or H.323.

Mail Transfer Agent

The e-mail is one of the most important services of internet. It is a server software required to transfer e-mails. The generic name of such software is MTA (Mail Transfer Agent). Modern MTA should support virtual domains, domain masquerading, domain routing. Also required property is a support for dialed networks.

The required condition for MTA is the ability to control service exchange. Many of the older servers did not enable to control exchange or they were inproperly configured and thus they became the facility for exchange of spam.

Nowadays it is required to support the encrypted communication. Other requirement is an ability to communicate with other software, which enables to filter or modify messages. Such software could filter viruses or spam or perform other required actions. Typical modifications of e-mails is the deletion of attachments with specific extensions which compose security risk, redundant parts removal, signature addition. All of this is supported by Linux.

Proxy Server

Proxy server is a server application which exchanges the communication between internet and hosts in the local area network. Classical proxy servers exchange services http, https, ftp, gopher and similar. It is required to exchange other protocols by the socks protocol or by other dedicated proxy servers. Linux enables both means of communication exchange. The classical proxy server served by squid suite is enhanced by cache, which lighten the network load. The squid suite enables to authenticate users and to control the access of them to resources by various criteria. It also enables to control the bandwidth assigned to users or groups. Naturally, it logs every communication.

Enterprise Network, in which Every User Has its Own Sit

The proxy server could exchange internet services for users authorised by IP addresses of their workstations. This IP address could identify the originating workstation.

Enterprise Network with Variable Sits

Proxy server could exchange internet services for authorised users authenticated by login and password. User can use the internet exchange for a specified time period after password input.

Enterprise Network with Defined Bandwith Assignment

It is often needed to assignd bandwidth separately for users or groups of users by priority. Especially when relatively slow internet connection is in use. It is possible to create bandwidth limits for users or group users in squid proxy suite.