Modes Explained

🎛 Modes Explained

GoodByeDPI GUI offers three modes. This page explains what each does, when to use it, and how they differ.

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🧠 Background: What is DPI?

Deep Packet Inspection (DPI) is a technology ISPs use to inspect the contents of your internet traffic. It's often used to:

• 🚫 Block specific websites
• 🐢 Throttle certain services
• 📊 Log traffic patterns

GoodbyeDPI doesn't encrypt your traffic (that's a VPN's job). Instead, it tricks DPI systems by fragmenting the very first packet of each connection, so the DPI filter can't identify what you're connecting to.

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⚡ Mode 1: Fast (Recommended)

Flag	-6
Technique	Reverse fragmentation + fake SEQ
Best for	Most ISPs worldwide
Success rate	⭐⭐⭐⭐⭐ (highest)

How it works

Splits the TLS Client Hello packet into fragments and sends them in reverse order, plus injects a fake packet with a wrong TCP sequence number that the DPI sees first.

When to use

Start here. It's the default for a reason — works on most ISPs and gives the best speed.

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🛡 Mode 2: Compatible (Fallback)

Flag	-5
Technique	Auto-TTL detection + gentler fragmentation
Best for	ISPs where Fast mode causes issues
Success rate	⭐⭐⭐⭐

How it works

Uses automatic TTL detection to figure out how far the fake packet needs to travel, then fragments more conservatively.

When to use

Try this if:

• Fast mode causes slow loading or hanging connections
• Some sites work but others don't
• You're on a mobile hotspot or unusual network

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🔧 Mode 3: Custom

Flag	(your choice)
Technique	Anything GoodbyeDPI supports
Best for	Power users, troubleshooting, edge cases
Success rate	Depends entirely on your flags

How it works

You supply the arguments yourself. The app passes them straight to goodbyedpi.exe.

When to use

• Fast & Compatible both fail
• You want to test a specific combination
• You're following a tutorial for your ISP
• You want a highly-specific setup

Example combinations

For stubborn ISPs:

-f 2 -e 40 --native-frag --reverse-frag --max-payload

Aggressive bypass:

-9 --fake-gen 5 --fake-resend 2 --auto-ttl --min-ttl 3

With DNS redirection:

-6 --dns-addr 1.1.1.1 --dns-port 53 --dnsv6-addr ::1 --dnsv6-port 53

📖 See Custom Arguments for the full reference.

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🎯 Which Mode Should I Pick?

        ┌─────────────────────────┐
        │   Websites not opening? │
        └────────────┬────────────┘
                     │
                     ▼
        ┌─────────────────────────┐
        │  Try  ⚡ Fast  first.    │
        └────────────┬────────────┘
                     │
         ┌───────────┴────────────┐
         │                        │
      Works ✅               Doesn't work ❌
         │                        │
         ▼                        ▼
     🎉 Done!         ┌──────────────────────┐
                      │  Try 🛡 Compatible.   │
                      └──────────┬───────────┘
                                 │
                     ┌───────────┴──────────┐
                     │                      │
                  Works ✅              Doesn't work ❌
                     │                      │
                     ▼                      ▼
                 🎉 Done!        ┌──────────────────────┐
                                 │  Go 🔧 Custom mode.   │
                                 │  See Custom Args.     │
                                 └──────────────────────┘

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⚖️ Side-by-Side Comparison

Aspect	⚡ Fast	🛡 Compatible	🔧 Custom
Complexity	Simple	Simple	Advanced
Speed impact	None	None	Depends
Compatibility	High	Higher	Varies
Good for	Most users	Fallback	Experts
Args	-6	-5	Your choice
Default?	✅ Yes	—	—

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🔬 Technical Details

Both Fast and Compatible use GoodbyeDPI's built-in mode shortcuts:

Flag	Internal preset
-5	--auto-ttl --min-ttl 3 --set-ttl 4
-6	--set-ttl 4 --wrong-seq
-9	Full suite (default GoodbyeDPI behavior)

The presets are documented in the official GoodbyeDPI README.

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💡 Pro Tips

• 🔄 Always try Fast first. It solves 90% of cases.
• 🎯 Don't stack modesets. Using -6 -5 together is undefined behavior.
• 📝 Save your working args. If a Custom combo works, copy it somewhere safe.
• 🧪 Test after 30 seconds. Give pages time to fully load before concluding it doesn't work.
• 🚫 No VPN simultaneously. They'll fight each other.

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Next: Learn about flags in Custom Arguments 🔧