1) Filter Table
Filter is default table for iptables. So, if you don’t define you own table, you’ll be using filter table. Iptables’s filter table has the following built-in chains.
Handa Wang superwhd
nerdalert
/ Netfilter-IPTables-Diagrams.md
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April 4, 2026 01:12
Linux NetFilter, IP Tables and Conntrack Diagrams
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| Latency Comparison Numbers (~2012) | |
| ---------------------------------- | |
| L1 cache reference 0.5 ns | |
| Branch mispredict 5 ns | |
| L2 cache reference 7 ns 14x L1 cache | |
| Mutex lock/unlock 25 ns | |
| Main memory reference 100 ns 20x L2 cache, 200x L1 cache | |
| Compress 1K bytes with Zippy 3,000 ns 3 us | |
| Send 1K bytes over 1 Gbps network 10,000 ns 10 us | |
| Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD |
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| host github.com | |
| user git | |
| hostname ssh.github.com | |
| port 443 | |
| proxycommand socat - PROXY:<hostname>:%h:%p,proxyport=<port> |