Category: tcp-ip

Analysis of HTTP message #2

This is the analysis of the second frame which I posted in my first post  2)  Timestamp 0.000044  I won’t describe everything that I already talked about in the first post instead only the necessary stuff.  2nd IP packet contains the TCP SYN-ACK segment which is the response of server side.

When to Send an ACK Segment

During one of my experimental studies I noticed a pattern in TCP ACK’s frequency. ACK segments are sent after receiving every 2 TCP segment. I kept asking why not 3 or 1 but 2. Then I found the answer in RFC1122 “Requirements for Internet Hosts — Communication Layers” when I was trying to find some information
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TCP fast retransmission

During analysis of my ESX server, vsphere client communication I have encountered the following packet capture. My vsphere client keeps asking for a lost segment with ACK number 1583183 for 9 times after which according to wireshark analysis TCP Fast Retransmission which is one of the ways of handling congestion is engaged. When I check
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Analysis of HTTP message #1

I am going to analyse a simple HTTP request response at packet level from application layer down to data link layer in this post. I took a sample packet capture by connecting to my web page which displays only “Hello World!” on an Apache web server. There are 10 ethernet frames captured and I will
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IP Fragmentation

In one of my previous posts ( , I wrote about IP fragmentation. This time I would like to show some wireshark screen shots showing a single IP packet consisting of 3 fragmentations to see the IP header fields used in fragmentation process. This IP packet is carrying an HTTP response: List of packets in
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Path MTU, IP Fragmentation and MSS

I would like to write about Path MTU discovery and IP Fragmentation in this post and the relation between them. As per the topology above, if the host LINUX1 is sending a packet to LINUX3 device. Packet has to go through a path in which there are various MTU sizes involved. In the past I
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