The proceedings constitute papers presented in the 26th International Conference, DCCN 2023, held in Moscow, Russia, during September 25-29, 2023. The 8 full papers were carefully reviewed and selected from 122 submissions. They cover variety of topics including networks architecture, network protocols, distributed computer systems, distributed communication systems, simulation, stochastic processes, queueing and reliability theory, Internet and web applications and services, wireless networks, Internet of things, performance analysis, and high-altitude communication platforms. .