How TCP really works: MTU vs MSS
Wireshark TCP Deep Dive continues: You need to understand this - whats the difference between Maximum Transmission Unit (MTU) vs Maximum Segment Size (MSS).
// MENU //
00:00 ▶️ Coming Up
00:25 ▶️ Intro
00:32 ▶️ Chris introduction
00:47 ▶️ Topic: Maximum Segment Size (MSS)
01:27 ▶️ Explaining Maximum Transmission Unit (MTU)
08:42 ▶️ Interface layout
10:25 ▶️ David Bombal "War Story"
12:00 ▶️ Wireshark demo
13:26 ▶️ Increasing the MTU on your device for larger connections
16:27 ▶️ Difference between MTU and MSS
19:36 ▶️ Wireshark demo (cont'd)
24:58 ▶️ Using Path MTU Discovery
27:02 ▶️ Ping and Wireshark demo
33:32 ▶️ Cool trick for Mac system
35:08 ▶️ TCP/MSS Clamping
38:21 ▶️ Chris Greer "War Story"
51:09 ▶️ What happens if you can't capture a server
55:08 ▶️ MSS Adjustment commands
56:55 ▶️ Tunnel Path MTU Discovery
57:40 ▶️ Figuring out 1432
01:02:52 ▶️ Conclusion
01:04:48 ▶️ "Cool features" in Wireshark
Previous video: https://youtu.be/rmFX1V49K8U
// Wireshark PCAP files //
MTU PCAP: https://github.com/packetpioneer/youtube/blob/main/PMTUD.pcapng
War Story PCAP Client: https://github.com/packetpioneer/youtube/blob/main/slowfile-clientside.pcapng
War Story PCAP Server: https://github.com/packetpioneer/youtube/blob/main/slowfile-serverside.pcapng
Special “Thumbs Up” and “Subscribe” PCAP: https://github.com/packetpioneer/youtube/blob/main/tcp-streamexport.pcapng
// VLAD SOCIAL //
Twitter: https://twitter.com/Packet_vlad
PMTUD Blog: http://www.packettrain.net/2016/09/21/pmtud-or-not/
Thanks Vladimir Gerasimov!
// GOOD READING //
Network Implications of PMTUD: https://www.ipspace.net/kb/Internet/PMTUD/30-network-implications.html
Path MTU Discovery: https://www.ipspace.net/kb/Internet/PMTUD/20-mtu-discovery.html
Resolve IPv4 Fragmentation, MTU, MSS, and PMTUD Issues with GRE and IPsec: https://www.cisco.com/c/en/us/support/docs/ip/generic-routing-encapsulation-gre/25885-pmtud-ipfrag.html
Configuring TCP MSS Adjustment: https://www.cisco.com/c/en/us/td/docs
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Chapters (22)
Coming Up
0:25
Intro
0:32
Chris introduction
0:47
Topic: Maximum Segment Size (MSS)
1:27
Explaining Maximum Transmission Unit (MTU)
8:42
Interface layout
10:25
David Bombal "War Story"
12:00
Wireshark demo
13:26
Increasing the MTU on your device for larger connections
16:27
Difference between MTU and MSS
19:36
Wireshark demo (cont'd)
24:58
Using Path MTU Discovery
27:02
Ping and Wireshark demo
33:32
Cool trick for Mac system
35:08
TCP/MSS Clamping
38:21
Chris Greer "War Story"
51:09
What happens if you can't capture a server
55:08
MSS Adjustment commands
56:55
Tunnel Path MTU Discovery
57:40
Figuring out 1432
1:02:52
Conclusion
1:04:48
"Cool features" in Wireshark
🎓
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