**ManTech** is seeking an experienced **Linux and Ruby on Rails Developer** with a strong background in **Telephony Engineering** to serve on a Dedicated Support Team of Network Telephony Installers supporting the Voice Program Recap Office (VPRO). In this role, you will leverage your expertise in Linux systems, Ruby programming, Ruby on Rails, and telephony systems to design, develop, and maintain voice media gateways that integrate with telephony infrastructure. You will be responsible for developing server-side logic, optimizing performance, integrating with telephony systems, and ensuring the smooth operation of complex systems. **Responsibilities include but are not limited to:** + Design, implement, and maintain web applications using Ruby and **Ruby on Rails** . + Work on integrating telephony systems (e.g., VoIP, analog, ISDN) along with voice media gateways and associated service modules + Manage and configure **Linux servers** (Ubuntu, CentOS, etc.) for hosting applications, ensuring performance, stability, and security. + Develop and Test on Linux based servers. Must be capable of developing and installing PowerBuilder based programs and Korn shell based servers. + Troubleshoot, configure, and optimize telephony software + Work independently developing and testing servers. + Monitor server performance, troubleshoot issues, and optimize systems for scalability and reliability. + Experience editing, updating, and modernizing legacy code. + Maintain clear technical documentation for telephony integration and deployment processes. **Minimum Qualifications:** + Strong experience with **Ruby programming** and understanding of the **Ruby on Rails** framework. + Advanced knowledge and hands on experience with telephony systems and **Linux server management** , including installation, configuration, troubleshooting, and performance optimization + Strong verbal and written communication skills to interact effectively with cross-functional teams. + BA/BS and 2 years of experiences, or a combination of education and work experience equivalent to 6 years. **Preferred Qualifications:** + Experience integrating telephony systems with web applications (e.g., handling inbound/outbound calls, IVR, call routing). + Knowledge of security best practices for telephony, server administration, and web applications. + Some experience with implementation on the Sponsor's new unclassified network LAN infrastructure. + Minimum 2 years of experience with implementation of the following infrastructure networks: + Sponsor's classified LAN infrastructure (including scripting, configuration, cutover and troubleshooting) + Sponsor's unclassified LAN infrastructure (including scripting, configuration, cutover and troubleshooting) + Qualified in Oracle Database Administrator. + Minimum 2 years of experience installing and troubleshooting telephone hardware and media gateways on the Sponsors classified and unclassified networks. + Experience provisioning telephony services. _Hours of coverage:_ Hours will depend on the specific team being supported. Generally, requests are to provide support between the hours of 6:00 a.m. – 6:00 p.m. **Security Clearance Requirements:** + Current/active TS/SCI with Polygraph. **Physical Requirements:** + Must be able to remain in a stationary position 50%. + Must be able to move/traverse within and between buildings and offices. + Must be able to position self to maintain equipment and cabling, including under the desks, while moving floor tiles, and in server closets, some of which may be confined spaces. + Able to operate a computer and other office productivity machinery, such as a calculator, copy machine and computer printer.  ManTech International Corporation, as well as its subsidiaries proactively fulfills its role as an equal opportunity employer. We do not discriminate against any employee or applicant for employment. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, or status as a protected veteran. If you are a qualified individual with a disability and require a reasonable accommodation to apply for a position with ManTech through its online applicant system, please email us at careers@mantech.com and provide your name and contact information.