Network traffic

Overview

Network traffic에 대한 기술 문서입니다.

Summary

• 무엇인가? - Network traffic
• 왜 필요한가? - HPC 및 서버 환경에서 필수 개념
• 언제 사용하는가? - 서버 구성, 성능 튜닝, 문제 해결 시

Purpose

이 문서가 존재하는 이유

• Goal: Network traffic에 대한 기술 정보 제공
• Scope: Network traffic의 개념, 사용법, 설정
• Non-goals: 다른 주제로의 확장

Key Concepts

Concept	Description	Related
Network traffic	HPC/서버 환경에서 중요한 기술 개념	Linux, Server

Detailed Explanation

• Network

In freebsd, session table provides real time rx/tx information for each connection. In Linux netfilter router, connections table only includes information on end of connections by default. from Linux kernel version >= 2.6.18, we can use conntract or conntrackd daemon, This tool can be used to search, list, inspect and maintain the connection tracking subsystem of the Linux kernel.

Conntrack points in Netfilter

conntrack module traces the connection status of trackable protocols (specific protocols, not all.) Set nf_contrack_acct $ sysctl -w net.netfilter.nf_conntrack_acct=1 Install contrack utility, if you do not have yet $sudo apt-get install conntrack # conntrack -L #conntrack -L -p tcp --dport 22 #conntrack -U -p tcp --dport 22 --mark 10 it can also block TCP traffic when

• stateful rule-set that drops traffic in INVALID state
• /proc/sys/net/netfilter/nf_conntrack_tcp_loose to zero.
• # conntrack -D -p tcp --dport 22

#conntrack -E There are bunch of network monitoring tools are available and this discussion shows most of them

• nethogs monitors traffic going to/from a machine, per process
• nettop shows packet types, sorts by either size or number of packets.

Best Practices

• 최신 버전 사용 권장
• 공식 문서 참고
• 테스트 환경에서 먼저 검증

References

• Network traffic

Related Pages

• Linux
• Server
• Hardware
• Network

Knowledge Graph

Related

→ Network performance test → RDMA → NIC Bonding → Network → IPMI → SDN → NFS