# a problem on SCTP INIT



## prypiat (Mar 10, 2014)

I have two virtual machine, both installed FreeBSD 10 / i386 / with generic KERNEL
(the host is CentOS 6.5 x86-64 with KVM)

The first virtual machine named freetest0 and second is freetest1

freetest0 = freebsd 10 / i386 / the IF is vtnet2 192.168.6.100
freetest1 = freebsd 10 / i386 / the IF is vtnet2 192.168.6.110

I want to test the speed between to freetest(s) IF.
But, the problem is they cannot get connected by SCTP. the TCP and UDP are well.

Whatever I use iperf3 (with SCTP support) and netperfmeter, they cannot get connected by SCTP.

```
#the server is freetest1
    root@freetest1:~ # netstat -an -f inet
    Active Internet connections (including servers)
    Proto Recv-Q Send-Q Local Address          Foreign Address        (state)
    tcp46      0      0 *.9000                 *.*                    LISTEN
    tcp4       0      0 192.168.0.110.22       192.168.0.1.39754      ESTABLISHED
    tcp4       0      0 192.168.0.110.22       192.168.0.1.39752      ESTABLISHED
    tcp4       0      0 127.0.0.1.25           *.*                    LISTEN
    tcp4       0      0 *.22                   *.*                    LISTEN
    udp46      0      0 *.9000                 *.*                    
    udp4       0      0 *.514                  *.*                    
    Active SCTP associations (including servers)
    Proto  Type  Local Address          Foreign Address        (state)
    sctp46 1to1  fe80::5054:ff:fe.9000                         LISTEN
                 192.168.8.110.9000     
                 fe80::5054:ff:fe.9000  
                 192.168.6.110.9000     
                 fe80::5054:ff:fe.9000  
                 192.168.0.110.9000     
                 127.0.0.1.9000         
                 fe80::1.9000           
                 ::1.9000               
    sctp46 1toN  fe80::5054:ff:fe.9001                         LISTEN
                 192.168.8.110.9001     
                 fe80::5054:ff:fe.9001  
                 192.168.6.110.9001     
                 fe80::5054:ff:fe.9001  
                 192.168.0.110.9001     
                 127.0.0.1.9001         
                 fe80::1.9001           
                 ::1.9001  



 

    root@freetest0:~ # netperfmeter 192.168.6.110:9000
    Network Performance Meter - Version 1.0
    ---------------------------------------
    
    Active Mode:
       - Measurement ID  = 4bc75bae
       - Remote Address  = 192.168.6.110:9000
       - Control Address = 192.168.6.110:9001 - connecting ...
    
    #<cannot get connected>
    
    
    
    root@freetest0:~ # tcpdump -i vtnet2
    tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
    listening on vtnet2, link-type EN10MB (Ethernet), capture size 65535 bytes
    14:11:03.839031 IP 192.168.6.100.55228 > 192.168.6.110.5201: Flags [S], seq 1318388212, win 65535, options [mss 1460,nop,wscale 6,sackOK,TS val 2652085 ecr 0], length 0
    14:11:03.868787 IP 192.168.6.110.5201 > 192.168.6.100.55228: Flags [R.], seq 0, ack 1318388213, win 0, length 0
    14:11:35.235362 IP 192.168.6.100.52018 > 192.168.6.110.9001: sctp (1) [INIT] [init tag: 3995201801] [rwnd: 1864135] [OS: 10] [MIS: 2048] [init TSN: 332259025] 
    14:11:38.256378 IP 192.168.6.100.52018 > 192.168.6.110.9001: sctp (1) [INIT] [init tag: 3995201801] [rwnd: 1864135] [OS: 10] [MIS: 2048] [init TSN: 332259025] 
    14:11:40.256418 IP 192.168.6.100.52018 > 192.168.6.110.9001: sctp (1) [INIT] [init tag: 3995201801] [rwnd: 1864135] [OS: 10] [MIS: 2048] [init TSN: 332259025] 
    14:11:44.256099 IP 192.168.6.100.52018 > 192.168.6.110.9001: sctp (1) [INIT] [init tag: 3995201801] [rwnd: 1864135] [OS: 10] [MIS: 2048] [init TSN: 332259025] 
    14:11:52.254442 IP 192.168.6.100.52018 > 192.168.6.110.9001: sctp (1) [INIT] [init tag: 3995201801] [rwnd: 1864135] [OS: 10] [MIS: 2048] [init TSN: 332259025]
    
    root@freetest1:~ # tcpdump -i vtnet2
    tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
    listening on vtnet2, link-type EN10MB (Ethernet), capture size 65535 bytes
    14:11:35.979349 IP 192.168.6.100.52018 > 192.168.6.110.9001: sctp (1) [INIT] [init tag: 3995201801] [rwnd: 1864135] [OS: 10] [MIS: 2048] [init TSN: 332259025] 
    14:11:39.000411 IP 192.168.6.100.52018 > 192.168.6.110.9001: sctp (1) [INIT] [init tag: 3995201801] [rwnd: 1864135] [OS: 10] [MIS: 2048] [init TSN: 332259025] 
    14:11:41.000495 IP 192.168.6.100.52018 > 192.168.6.110.9001: sctp (1) [INIT] [init tag: 3995201801] [rwnd: 1864135] [OS: 10] [MIS: 2048] [init TSN: 332259025] 
    14:11:45.000116 IP 192.168.6.100.52018 > 192.168.6.110.9001: sctp (1) [INIT] [init tag: 3995201801] [rwnd: 1864135] [OS: 10] [MIS: 2048] [init TSN: 332259025] 
    14:11:52.998491 IP 192.168.6.100.52018 > 192.168.6.110.9001: sctp (1) [INIT] [init tag: 3995201801] [rwnd: 1864135] [OS: 10] [MIS: 2048] [init TSN: 332259025]
```


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## prypiat (Mar 11, 2014)

The answer is that checksum error after packet analysis.


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