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Andromeda_x · 2016-12-03, 08:24

Hi,

can somebody explain tcpdump output

Code:

22:37:26.487649 IP (tos 0x0, ttl 64, id 8792, offset 0, flags [none], proto TCP (6), length 64)

    ipxe.coguar.com.25653 > moon.coguar.com.iscsi-target: Flags [S], cksum 0xff6e (correct), seq 518423897, win 65532, options [nop,nop,TS val 434086 ecr 0,nop,nop,sackOK,nop,wscale 9,mss 1460], length 0

22:37:26.487693 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 60)

    moon.coguar.com.iscsi-target > ipxe.coguar.com.25653: Flags [S.], cksum 0x81dd (incorrect -> 0x3d9e), seq 682718093, ack 518423898, win 14480, options [mss 1460,sackOK,TS val 7274121 ecr 434086,nop,wscale 5], length 0

22:37:26.487797 IP (tos 0x0, ttl 64, id 9049, offset 0, flags [none], proto TCP (6), length 52)

    ipxe.coguar.com.25653 > moon.coguar.com.iscsi-target: Flags [.], cksum 0xa2f8 (correct), seq 1, ack 1, win 512, options [nop,nop,TS val 434086 ecr 7274121], length 0

22:37:26.487827 IP (tos 0x0, ttl 64, id 9305, offset 0, flags [none], proto TCP (6), length 100)

    ipxe.coguar.com.25653 > moon.coguar.com.iscsi-target: Flags [P.], cksum 0x8531 (correct), seq 1:49, ack 1, win 512, options [nop,nop,TS val 434086 ecr 7274121], length 48

22:37:26.487850 IP (tos 0x0, ttl 64, id 36103, offset 0, flags [DF], proto TCP (6), length 52)

    moon.coguar.com.iscsi-target > ipxe.coguar.com.25653: Flags [.], cksum 0x81d5 (incorrect -> 0xa303), seq 1, ack 49, win 453, options [nop,nop,TS val 7274121 ecr 434086], length 0

22:37:26.487996 IP (tos 0x0, ttl 64, id 9562, offset 0, flags [none], proto TCP (6), length 192)

    ipxe.coguar.com.25653 > moon.coguar.com.iscsi-target: Flags [P.], cksum 0xbd86 (correct), seq 49:189, ack 1, win 512, options [nop,nop,TS val 434086 ecr 7274121], length 140

22:37:26.488012 IP (tos 0x0, ttl 64, id 36104, offset 0, flags [DF], proto TCP (6), length 52)

    moon.coguar.com.iscsi-target > ipxe.coguar.com.25653: Flags [.], cksum 0x81d5 (incorrect -> 0xa256), seq 1, ack 189, win 486, options [nop,nop,TS val 7274121 ecr 434086], length 0

22:37:26.488321 IP (tos 0x0, ttl 64, id 36105, offset 0, flags [DF], proto TCP (6), length 100)

    moon.coguar.com.iscsi-target > ipxe.coguar.com.25653: Flags [P.], cksum 0x8205 (incorrect -> 0xa398), seq 1:49, ack 189, win 486, options [nop,nop,TS val 7274121 ecr 434086], length 48

22:37:26.488361 IP (tos 0x0, ttl 64, id 36106, offset 0, flags [DF], proto TCP (6), length 52)

    moon.coguar.com.iscsi-target > ipxe.coguar.com.25653: Flags [F.], cksum 0x81d5 (incorrect -> 0xa225), seq 49, ack 189, win 486, options [nop,nop,TS val 7274121 ecr 434086], length 0

22:37:26.488599 IP (tos 0x0, ttl 64, id 9820, offset 0, flags [none], proto TCP (6), length 52)

    ipxe.coguar.com.25653 > moon.coguar.com.iscsi-target: Flags [F.], cksum 0xa20b (correct), seq 189, ack 49, win 512, options [nop,nop,TS val 434086 ecr 7274121], length 0

22:37:26.488623 IP (tos 0x0, ttl 64, id 36107, offset 0, flags [DF], proto TCP (6), length 52)

    moon.coguar.com.iscsi-target > ipxe.coguar.com.25653: Flags [.], cksum 0x81d5 (incorrect -> 0xa224), seq 50, ack 190, win 486, options [nop,nop,TS val 7274121 ecr 434086], length 0

22:37:26.565475 IP (tos 0x0, ttl 64, id 10078, offset 0, flags [none], proto TCP (6), length 52)

    ipxe.coguar.com.25653 > moon.coguar.com.iscsi-target: Flags [.], cksum 0xa208 (correct), seq 190, ack 50, win 512, options [nop,nop,TS val 434088 ecr 7274121], length 0

What is meaning of "(incorrect -> 0xa224)" in tcpdump output? Does it a symptom of a problem I have with ipxe+sanhook?

It is very interesting situation as on other test computer iSCSI target can be attached without any issue (Authentication set to None)...

Code:

root@vega:~/iscsi# iscsiadm -m session

tcp: [38] 192.168.0.64:3260,1 iqn.2016-12.com.coguar.moon:storage.lun0

root@vega:~/iscsi#

Checking tcpdump in wireshark I see next "conversation" beween the computers

iPXE test computer to iSCSI server (iSCSI protocol :: Login Command)

Code:

Key/Value Pairs

    KeyValue: InitiatorName=iqn.2010-10.org.ipxe.dophin.client1

    KeyValue: TargetName=iqn.2016-12.com.coguar.moon:storage.lun0

    KeyValue: SessiionType=Normal

    KeyValue: AuthMethod=None

  Padding: 0000

iSCSI server replies to iPXE test computer (iSCSI protocol:: Login Response)

Code:

Status: Target not found (0x0203)

NOTE: tcpdump -i eth0 host ipxe -w /tmp/tcpdump.cap

Any thought on what is going on between iPXE test computer and iSCSI server? Why do the computers not agree to work together?

Question: I was looking how to add an attachment (tcpdump capture of iSCSI negotiation) to this post and forum system gave me next message

Code:

Please correct the following errors before continuing:

The type of file that you attached is not allowed. Please remove the attachment or choose a different type.

What is proper procedure to add a file of any type?

Andromeda X