i am trying to get or put with TFTP protocol. I set the TFPT server and everything worked but stopped working lately. I am able to connect to the server but am getting an error "unknown option -?" when inspecting the Syslog. When running Tcpdump i see the message is "19 RRQ filename netascii"
i have looked for a couple of days in the net but with no success.
from RFC 1350
opcode operation
1 Read request (RRQ)
2 Write request (WRQ)
3 Data (DATA)
4 Acknowledgment (ACK)
5 Error (ERROR)
2 bytes string 1 byte string 1 byte
------------------------------------------------
| Opcode | Filename | 0 | Mode | 0 |
------------------------------------------------
This is what you have to see in your RRQ or WRQ packet
Related
I'm using ssh to do some computations on a remote server, which is in linux whereas my computer is Windows 10. I would like to be able to see plots from gnuplot, but a priori it does not plot anything.
From what I've read, it seems I need to setup X11 forwarding. I installed VcXsrv X server with everything default, and set "export DISPLAY=localhost:0" in the ssh terminal, but then I get an error like pictured below.
From here it seems less clear to me what I should do. It seems many people have a variety of issues which lead to this error, but I don't think I'm doing anything particularly complicated. Some things have mentioned checking some kind of config file or trying something like localhost:10 or 137 or something else, but I'm not even sure if my profile has that kind of config file, and I have no clue how to choose what number to put after localhost.
I'm quite new to this kind of thing so any help is appreciated.
I cannot help with the question of how to get the Windows end of an X11 connection working, but depending on the resolution or type of graphics output needed you may be able to use one of the other gnuplot output modes.
"set term dumb" will send low resolution character-cell graphics back to the terminal window you are typing in. This should work anywhere. The output would look like this:
1 + ***
| ** **
| * * sinc(x) *******
0.8 | * *
| * *
| * *
0.6 | * *
| * *
| * *
0.4 | * *
| * *
0.2 | * *
| ** * * **
| **** *** * * *** ****
0 | *** ** * * ** ***
|** ** * * ** ***
| *** ** ** ***
-0.2 | ****** ******
|
|
-0.4 +-------------------------------------------------------------------------------+
-10 -5 0 5 10
If on the Windows end you run a terminal emulator capable of sixel graphics, then much higher resolution color graphics can be sent directly back to the terminal using "set terminal sixel". See screenshot below.
More complicated options are also possible that involve piping files (png jpeg svg pdf ...) back through the x11 connection for separate display on the Windows end.
I get Request body data from excel file.
I have already covert excel to csv format.
I have kind of able to find a solution but it is not working 100% as jsonbody format in not fetching data correctly is shows forward slash in csv import data from runner collections.
Request Body
{{jsonBody}}
Set Global variables jsonBody
Run collection select data file as csv file as per screenshot request body shows with forward slash.
After running the collection I'm getting body incorrect version with forward slash.
This below screenshot show correct version on csv data I require to remove forward slash from csv data
I had similar issue with postman and realized my problem was more of a syntax issue.
Lets say your cvs file has the following columns:
userId | mid | platform | type | ...etc
row1 94J4J | 209444894 | NORTH | PT | ...
row2 324JE | 934421903 | SOUTH | MB | ...
row3 966RT | 158739394 | EAST | PT | ...
This is how you want your json request body to look like:
{
"userId" : "{{userId}}",
"mids":[{
"mid":"{{mid}}",
"platform":"{{platform}}"
}],
"type":["{{type}}"],
.. etc
}
Make sure your colums names match the varibales {{variableName}}
The data coming from CSV is already in a stringified format so you don't need to do anything in pre-request.
example:
let csv be
| jsonBody |
| {"name":"user"}|
Now in postman request just use:
{{jsonBody}}
as {{column_name}} will be considered as data varaible so , in your case {{jsonBody}}
csv:
make sure you save this as csv file :
Now in request use :
output:
if you want to add the json body as value of another then just use :
Output:
All connections are InActConn
I'm a newbie using LVS. I've tried LVS/TUN and LVS/DR, the result is the same, all connections are InActConn. But the realservers can be reach (through PING). Pls help!!!
OS: CentOS 6.2
RemoteAddress:Port Forward Weight ActiveConn InActConn
UDP 192.168.10.240:2345 rr
-> 192.168.10.251:2345 Tunnel 1 0 10
-> 192.168.10.252:2345 Tunnel 1 0 9
-> 192.168.10.253:2345 Tunnel 1 0 9
This is the expected behavior for services not maintaining connections, like UDP. You may want to read the LVS Howto, especially the part about Active/Inactive connections :
http://www.austintek.com/LVS/LVS-HOWTO/HOWTO/LVS-HOWTO.ipvsadm.html#ActiveConn
Old Question : But I got to this post from Google and want to paste my findings here.
In the above answer, the link pasted by #remi-ggacogne missed 1 step for Real server.
You have to turn rp_filter off (esp. in Centos / RHEL ) https://www.slashroot.in/linux-kernel-rpfilter-settings-reverse-path-filtering
Open /etc/sysctl.conf and paste below lines ( as per your network interface )
net.ipv4.conf.all.rp_filter = 0
net.ipv4.conf.default.rp_filter = 0
net.ipv4.conf.tunl0.rp_filter = 0
To make the above active -->
$systcl -p
What's the size of the ICMP packet payload when the type is 11, i.e. time exceeded?
Since it contains an IP header and the first 8 Bytes of the IP packet payload generating the ICMP message, I thought its size was 20 + 8 = 28.
I'm replaying some common user traffic with TTL=1. In the ICMP messages I have dumped I noticed that:
all ICMP packets generated by UDP packets have payload of size 28 Bytes
all those generated by TCP packets have payload of size 40 Bytes
Since I need to match ICMP time-exceeded messages with the packets that triggered them by comparing those bytes, this piece of information is essential, but I can't find figure out why this happens.
The problem is that you're quoting the 8-byte header payload from RFC 792, Page 4, but the requirements were changed by RFC 1812...
Time Exceeded Message (in RFC 792)
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Code | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| unused |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Internet Header + 64 bits of Original Data Datagram |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
RFC 1812, Section 4.3.2.3 dramatically increases the allowable payload in an ICMP Error message (emphasis mine):
4.3.2.3 Original Message Header
Historically, every ICMP error message has included the Internet
header and at least the first 8 data bytes of the datagram that
triggered the error. This is no longer adequate, due to the use of
IP-in-IP tunneling and other technologies. Therefore, the ICMP
datagram SHOULD contain as much of the original datagram as possible
without the length of the ICMP datagram exceeding 576 bytes. The
returned IP header (and user data) MUST be identical to that which
was received, except that the router is not required to undo any
modifications to the IP header that are normally performed in
forwarding that were performed before the error was detected (e.g.,
decrementing the TTL, or updating options).
The ICMP Errors you're generating from Scapy packets should contain all the information from the IP and TCP layers of the original packet.
As you noted, the ICMP payload is the IP header plus 8 octets of the original packet's payload. IP headers, however, are not always 20 octets long; 20 is only the minimum. The IP header itself may contain options, and the header length is indicated by the value in the IHL field of the header. See sec 3.1 of RFC 791. So it looks like the TCP packets have 12 additional octets of options in their IP headers. RFC 791 defines some standard options such as source routing and timestamping. You'll have to decode the header to determine what options are being used.
I would like to add for future reference that not only do ICMP payloads vary in size as Mike said, they might also be longer than 128 Bytes in the case of ICMP extensions for MPLS. See this draft for more information
I have a process that is kicked off by a scheduled batch file daily. I need to have error handling built in to restart the process if there is an error. All works great most days but I get a time out error once a month or so that is unavoidable. The process does not output an errorlevel to the bat file so I need to be able to parse the output file to determine if the process needs to restart.
I tried using the FOR /F function to pass the contents of line 12 as a variable to use in an IF statement but I have been unsuccessful. I can obviously skip to line 12 but then I am left dealing with the tokens of the remaining lines. Does anyone have any suggestions that I could try?
Output file when all is well:
(Line Numbers Added for Readability)
1 Pricing Script
2
3 ________________________________________________________________________
4
5 Retrieve Prices
6
7 Date of price file: 070912
8 Regular only
9 Connecting to server intdata.com
10 TCP/IP connection established
11
12 TySymb Interactive Data
+400 more lines
Output file when there is an error:
1 Pricing Script
2
3 ________________________________________________________________________
4
5 Retrieve Prices
6
7 Date of price file: 071012
8 Regular only
9 Connecting to server intdata.com
10 TCP/IP connection established
11 Time Out
12 General Time Out. The User ID and/or Password might be incorrect.
I would simply look for the error message in the output using FIND or FINDSTR. I wouldn't worry about the line number.
find "General Time Out. The User ID and/or Password might be incorrect." "yourFile.log" && (
echo Timeout occurred, you must put code here to restart
)
or
findstr /c:"General Time Out. The User ID and/or Password might be incorrect." "yourFile.log" && (
echo Timeout occurred, you must put code here to restart
)
This will test only line 12 of your file for a given string:
#echo off
for /f "skip=11 tokens=*" %%i in (your_log_filename) do (
echo %%i | find "General Time Out" >nul
goto check
)
:check
if errorlevel 1 (echo No Timeout occured!) else (echo Timeout occured)