The packet tag has no wiki summary.
-1
votes
1answer
26 views
Drop \secure\ packets from Firewall? [closed]
One of our customers (game servers) has linked us to a thread where other admins have reported an exploit that is being done with \secure\ packets. I am not entirely clear on what is being asked, ...
0
votes
1answer
26 views
Getting packet rate with tcpdump or iptables
I need to get the rate at which certain packets (i.e. LDAP) arrive on a interface in a linux environment.
I was thinking of using tcpdump to filter the wanted packets and subsequently monitor the ...
0
votes
0answers
38 views
Caculating packet offset
In Wireshark, if I want to write a filter which accepts only ICMP destination unreachable ( type 3 ) messages, the filter is icmp[0] == 3 .
How do I count the packet offset of 0 in this instance ?
...
0
votes
4answers
101 views
Smaller network packets vs bigger packets - confused
Some are saying that bigger packets are better to send then smaller.
But in this app: http://media.pearsoncmg.com/aw/aw_kurose_network_2/applets/message/messagesegmentation.html
The lower the packet ...
1
vote
2answers
83 views
Tracking actual packet path on a LAN
Is it possible to track the path a packet takes on a switched network. When I run a traceroute I get only the router and the destination. I know for a fact, however, that the packet must pass through ...
-1
votes
2answers
84 views
What happens when an unexpected packet arrives at a computer? [closed]
I have been wondering this for a few days. I basically understand how networks and packets work. But what happens when an unexpected packet arrives? Like, when I didn't send a request for a website's ...
1
vote
1answer
455 views
VMWare-ESXi server dropping packets, shaky connection
I have a few virtual servers running on a VMWare-ESXi server. One of those is a mailserver running Windows server 2003, Has been running quite well for a while now. About 4 days ago, the mailserver ...
1
vote
2answers
1k views
Intel 82579LM Gbit Ethernet Controller - magic packet (WOL) right after ping is not working
I am experiencing a very annoying and mysterious behavior when sending magic packets (for Wake On LAN) shortly after pinging an Intel 82579LM GigaBit Ethernet Controller (the onboard ethernet ...
0
votes
1answer
558 views
SMTP port open - but not open
As some of you might know, I am setting up an exchange server.
Now I ran into another problem:
I cannot connect to the SMTP service from outside the server!
The ports are opened in the gateway ...
2
votes
1answer
816 views
iptables drop packet by hex string match
I got this packet captured with tcpdump but I'm not sure how to use the --hex-string param to match the packet. Can someone show me how to do it?
11:18:26.614537 IP (tos 0x0, ttl 17, id 19245, offset ...
2
votes
1answer
239 views
Check what the average packet size is in a network (what firewall/router should I get)
Is there any way to do this?
We are looking into buying a Fortigate 100D but are unsure if it will hold up to our requirements.
http://www.fortinet.com/products/fortigate/100D.html
While the ...
0
votes
0answers
88 views
How to pervent vtp updates coming from vmware to go towards switch?
To get the background of this question please follow this link
http://security.stackexchange.com/questions/14803/using-nessus-an-alien-packet-from-switch-shut-down-my-ethernet-card-completely
I have ...
1
vote
0answers
535 views
Calculating the round trip time for ping packets
I am currently practicing for my network & communications course and have managed to confuse myself slightly on a question about packet round trip time. I have made a start but am now a bit stuck!
...
0
votes
1answer
176 views
How to block specific UDP packet outgoing from machine using iptables
I want to block specific UDP packet OUTGOING from my machine using iptables. Packet has a string in "hex in RAW"(?) i want to check packet by it.
Like: If UDP packet hex RAW match "test_text" - block ...
0
votes
3answers
240 views
TCP firewall allows connection to external server but blocks response packets?
Consider this basic network setup:
Client -> Router -> "Internet" -> Router -> Server
Problem: the client can open a connection to the server and send data ("request"), but the server data packets ...
0
votes
1answer
84 views
Tools to inspect an ethernet packet travels through host's interfaces?
I am debugging a local ethernet connection on a Linux machine. I want to inspect the ethernet packets as they travel. in and out current machines' interfaces. I do not have a GUI on the machine. Is ...
-1
votes
1answer
163 views
Checking HTTP response for website using Wireshark
Is there a specific way to know if the file that we download through a web server (e.g.: Java) can be verified through Wireshark?
I want to check if the file is working perfectly from internal and ...
4
votes
2answers
736 views
Configuring Frame Relay using a Switch Simulation - Packet Tracer
I have the following set up in Packet Tracer:
I am trying to configure frame-relay between the RTR-EDGE router, the RTR_ENG router and the RTR_SAL router using a frame-relay switch simulation (the ...
1
vote
4answers
356 views
iptables : How to calculate how many bytes there're in a packet?
I'm working on a firewall and I would like to know how to calculate how many bytes there're in a packet or at least have an idea what the averages are.
When I googled it, 1500 bytes was mentioned a ...
0
votes
1answer
142 views
iptables: is it possible to spoof NEW packets and make them look like ESTABLISHED packets?
See title for the question.
This question relates to a previous question wherein I asked the difference between NEW,ESTABLISHED and RELATED , see it here iptables: difference between NEW, ESTABLISHED ...
6
votes
1answer
1k views
iptables: difference between NEW, ESTABLISHED and RELATED packets
Part of a firewall on a server :
iptables -A INPUT -p tcp --dport 22 -m state NEW --state -m recent --set
iptables -A INPUT -p tcp --dport 22 -m state --state NEW -m recent --update --seconds 100 ...
0
votes
1answer
198 views
tcpdump vs netsniff-ng vs custom libpcap implementation [closed]
I'm looking to pick the brains of anyone experienced with building high performance packet capture devices. I have my own implementation written for tcpdump, but am considering moving to netsniff-ng ...
4
votes
1answer
353 views
Packet loss during TCP handshake
I have to implement a pseudo TCP handshake that leads into a file transfer. I have no problem doing the file transfer: simple send-acknowledge. What I can't wrap my head around is how to do the three ...
0
votes
1answer
89 views
size of packet icmp with netstat TX
I am confused with the size of packet icmp. I just did a simple initial netstat, where
for eth0 : TX-OK = 485
after 1 ping message is send, again I see in netstat TX-OK = 488
So, I just want to know ...
0
votes
1answer
179 views
What is Reverse Gossip Transfer Protocol?
Playing with wireshark, I see a bunch of packets that say something like
rgtp > https [ACK] Seq=???? Ack=?????? Win=????? Len=0
What is a Reverse Gossip Ttransfer Protocol? What is it used for, ...
2
votes
1answer
1k views
Linux bridge (brctl) is dropping packets
I have been researching this problem for a few days and have not found an answer yet. Your help will be really appreciated!
I have a few VMs (Virtual Machines) running on a physical server. The ...
4
votes
2answers
3k views
Can 3G networks be packet sniffed / analyzed?
Just wondering if 3G networks can be sniffed like public wifi networks, via wireshark for example (I'm almost sure this is not possible due to encryption, but I just want to make sure?)
0
votes
2answers
176 views
Linux not sending ICMP with iptables `--reject-with`
Using iptables I am trying to reject packets (I want to return an ICMP message).
iptables -A FORWARD [...] -j REJECT --reject-with icmp-port-unreach
The packets are dropped but using tcpdump I can ...
0
votes
1answer
2k views
Good packet generator tool for IPv6.. Does hping3 support IPv6?
Does anyone of you know any good packet generator tool for IPv6. I am very familiar with hping3, but don't know if it supports IPv6.
I am looking for something which can send, tcp, udp, icmp, and ...
2
votes
1answer
177 views
TCP sequence number and ACK number
Is the TCP sequence number just the ACK number + bytes received? Is it different when doing the 3-way handshake?
0
votes
1answer
49 views
Sharing connections on a circuit-switched network possible?
Is it possible to somehow share a circuit-switched connection? For example, could multiple computers be connected to a router which is connected to a circuit-switched network?
1
vote
2answers
75 views
Q: What does “all packets that fall through to the default rule should be dropped” mean?
What does "all packets that fall through to the default rule should be dropped" mean?
Does that mean my iptables rule should drop everything at start like this?
# Set the default policy to drop
$IPT ...
2
votes
1answer
172 views
Confusion about TCP packet analysis terms
I'm analyzing our network and have some confusion about the terms:
this is the 2-packet output from source to destination.
from these i have to get some features as describe, pls make me clear...
...
2
votes
3answers
7k views
How do you diagnose packet loss?
I realise this is very subjective and dependent on a number of variables, but I'm wondering what steps most folks go through when they need to diagnose packet loss on a given system?
1
vote
2answers
54 views
Computer sleep and wake up announcement on a network
I wonder if there's some sort of network packet that announces a computer going to sleep or waking up again.
If not, can you think of reasons why this would be a bad idea?
0
votes
2answers
1k views
When analyzing packets with Wireshark, is there a way to know which program is sending which packet?
is there an easy way to know from where the packets come from? Which program?
My pc which is on 192.168.0.100 is continuously sending packets (TCP and SMB) to an unknown host (192.168.1.99) and I ...
4
votes
2answers
2k views
How is packet collision avoided in full duplex mode?
While working in full duplex mode, one can send and receive packets simultaneously. Why don't the packets collide?
0
votes
1answer
302 views
Forward all data sent to XXX to BBB
I want to forward all that that is being sent to IP XXX and send it to IP BBB
Example:
A packet is being sent to IP 23.24.165.56, I want that packet to be sent to IP 127.0.0.1 instead.
Any ideas?
0
votes
1answer
121 views
Altq limits not being applied to UDP transfers
I have a OpenBSD server acting as a router/firewall with yhr packet filter ruleset shown below, a linux server, and a linux client.
When transferring files (using netcat) by TCP, the limits are ...
2
votes
1answer
372 views
Inaccurate bandwidth limiting in altq queues
I'm setting up an environment where I have one Linux server, one OpenBSD router and one Linux client and I want to be able to limit how much bandwidth the client should be able to use.
I've been ...
0
votes
1answer
371 views
How does ospf control flooding?
What method is used by ospf protocol to prevent looping of flooded packets for link state advertisements? The packet header does not contain any timestamp. How do the routers recognize that it is the ...
