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Is it possible to generate an IPv4 packet with an IPv4 packet header larger than 20 bytes on an IPv4 connections?

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  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide and accept your own answer.
    – Ron Maupin ♦
    Feb 19, 2018 at 4:51

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Is it possible to generate an IPv4 packet with an IPv4 packet header larger than 20 bytes on an IPv4 connections?

Yes, there are IPv4 options that may increase the packet header size. That is one of the things that IPv6 fixed. The maximum IPv4 packet header length is 60 bytes.

An IPv6 packet header is always 40 bytes.

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  • How do I "use" these options to capture a frame that will show the IP header being larger than 20 bytes?
    – John D
    Jun 6, 2017 at 23:01
  • I forgot to mention without IPv6. I've done some googling and Cisco's extended ping has the option to set IP Header options, but it seems extended ping is not available on windows.
    – John D
    Jun 6, 2017 at 23:02
  • You do not use those options to capture a frame. Frames are layer-2 datagrams, but IP is a layer-3 protocol that uses packets as a datagram. You can use a capture application to capture packets that have options. For the most part, IPv4 packets are only 20 bytes because IPv4 packets with options are often blocked by firewalls and routers. As you have discovered, you could use your Cisco router or switch to send packets with options. Host applications and OSes are off-topic here.
    – Ron Maupin ♦
    Jun 6, 2017 at 23:06
  • I meant how do I send packets with IPv4 options? I know that the options do not capture the frame, WireShark is used for that. My goal is to capture a frame with Wireshark that shows the IP header is longer than 20 bytes.
    – John D
    Jun 6, 2017 at 23:16
  • That is up to your application and/or host OS, which I have explained are both off-topic here. I'm not sure what routers and switches your company uses, but if you have Cisco devices, you can use those.
    – Ron Maupin ♦
    Jun 6, 2017 at 23:19

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