From RFC 3720: "The Small Computer Systems Interface (SCSI) is a popular family of protocols for communicating with I/O devices, especially storage devices…. The iSCSI protocol describes a means of transporting of the SCSI packets over TCP/IP, providing for an interoperable solution which can take advantage of existing Internet infrastructure, Internet management facilities and address distance limitations."
XXX - add a brief description of iSCSI history
Internet Archive: IBM Project Page
- TCP: iSCSI uses TCP as its transport protocol. The well known TCP port for iSCSI traffic is 3260. Pre-RFC implementations of iSCSI often used other ports.
XXX - Add example traffic here (as plain text or Wireshark screenshot).
Sample Capture scsi-osd-example-001.pcap in
The iSCSI dissector is fully functional. It supports drafts 8, 9, 11, 12 and 13. As far as the packet format is concerned draft 13 is identical to the official standard in RFC3720. (Rolled into RFC7143 )
For general use, it is best to have iSCSI desegmentation on and TCP desegmentation on. The dissector will automatically detect whether HeaderDigest is used or not for all supported versions of the protocol but not Datadigest. You need to make sure the correct setting is used in preferences for whether DataDigest is used or not or Wireshark will fail to decode the packets properly.
Update: The preferences were reworked to automatically detect digests:
- iscsi: automatically detect data segment digest
- remove two preference options related to iscsi header digest
XXX - Add a simple example capture file to the SampleCaptures page and link from here. Keep it short, it's also a good idea to gzip it to make it even smaller, as Wireshark can open gzipped files automatically.
A complete list of iSCSI display filter fields can be found in the display filter reference
Show only iSCSI traffic:
You cannot directly filter iSCSI protocols while capturing. However, if you know the TCP port used (see above), you can filter on that one.
Capture iSCSI traffic over the default port (3260):
tcp port 3260
I think RFC3720 PDU format is identical to draft13 anyone know for sure? ronnie s
Imported from https://wiki.wireshark.org/iSCSI on 2020-08-11 23:15:22 UTC