Questions tagged [packet]
The packet tag has no usage guidance.
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16 views
Is Network address translation (NAT) considered a type of packet mangling?
I am learning about iptables, netfilter and networking in general. I understand that iptables supports 5 different kinds of tables - raw, mangle, nat, filter and security.
From what I understand, ...
2
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0answers
13 views
FreeBSD: redirect some UDP traffic from one port to another
I have some specialized DNS servers running on FreeBSD 11. A few people keep hammering on them and I would like to give them different answers. So I'd like to divert UDP traffic from those hosts from ...
0
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1answer
32 views
Force jumbo packet fragmentation
We are in a cluster environment. We have compute nodes with jumbo packets enabled and a MTU of 9000. We are running into some issues in tracebacks to an address outside of our lan, where jumbo packets ...
-6
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1answer
50 views
How packet is transmitted over the network? [closed]
I am writing discrete event-driven simulator to measure time between sending datasets over network.
If multiple processes sends n packets through network they (packets) will go one after one through ...
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2answers
343 views
Openvpn fails behind firewall but another VPN Works
Well I have spent last 48 hours trying to debug this but I'm about to give up now.
Mobile carrier in our country has a daily social bundle in which we can use ONLY whatsapp, facebook and snapchat &...
1
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1answer
281 views
How to send outgoing TCP packets on Windows through a remote Linux server?
Let's say I have a Windows computer and a Linux server. I'm looking for a way to route outgoing TCP packets on the Windows computer (all ports) through the Linux server.
The Linux server would have ...
1
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1answer
959 views
Understanding SoftEther VPN packet log
Help me to identify each part of a packet log from softether VPN.
for example, the below given is a packet log.
2017-06-07,23:40:20.888,SID-USER-[L2TP]-15,SID-SECURENAT-1,CA9DC6D826F0,00AC3A3F04D0,...
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2answers
1k views
How to mark packets depending on hostname?
We can mark packets on the basis of IP addresses in the following way -
iptables -A FORWARD -t mangle -s 123.2.3.4 -j MARK --set-mark 1
How to mark packets depending on the hostname? I tried this - ...
0
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1answer
53 views
High Traffic from Content Delivery Networks
I am having trouble on our school network recently. When browsing the internet users will often get an error from the browser saying "No Internet DNS_PROBE_FINISHED_NXDOMAIN" but when they refresh the ...
0
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1answer
2k views
Transportation Layer vs Network Layer [closed]
I am a networking student, and I am learning about the OSI system for networks. The concepts for this system are all pretty complicated, but the main issue that I'm having is the main differences ...
0
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0answers
311 views
Route HTTP packets into tun/tap interface
What I simply want is to redirect all HTTP packet from any interface to my tun/tap interface. A scapy script will listen on this interface and do some treatments to these packets.
First, I created a ...
1
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1answer
777 views
Accept ICMP packets (ping) with specific length - Iptable rules
I am going to filter Ping request to my server, and only accepts ping request with length 920.
ping -l 920 serrveraddress
I am using the following two command in iptables
iptables -A INPUT -p icmp -...
-3
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1answer
94 views
Linux firewall packet handling
When a client communicates with a the server via HTTP, for example, there are many packets going in both directions. It means from the client to the server and vice versa.
I would like to ask how ...
0
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1answer
93 views
Drop packet containing the selected string
How can I drop all packets on windows server that are containing a specific string?
The string is: TSource
Windows Firewall doesn't seem to have this kind of option.
0
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1answer
178 views
Force Windows to send packets as soon as they arrive the nic
I have a network application running on Windows Server 2008 R2, that must send small packets in a very short time interval, each microsecond matters. My problem is that windows accumulates the packets ...
4
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1answer
8k views
Outbound Packets Dropping / Timeouts - Only with Azure
I have an issue with packets dropping to a third party data center in Florida, USA. The issue only occurs on Azure Virtual Machines, no matter which data center the VM is in. I've done the same tests ...
0
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1answer
434 views
Extremely flaky connection to our EC2 instance through one connection, but not others
We have a robotic coffee barista deployed at the Dell campus in North Austin, with internet service through Time Warner Cable.
We have been fighting intermittent connection losses between 10PM - 1AM ...
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0answers
950 views
Getting chunks of high ms when pinging local / external IP addresses?
I am having difficulty identifying what a specific problem with one of your vlaned networks.
They have a voip phone which regularly cuts out during long phone calls.
I have done several ping tests ...
-3
votes
1answer
1k views
iptables rules for blocking specific packets [closed]
Im using the following iptables rule:
iptables -A INPUT -p tcp -m tcp --tcp-flags PSH,ACK PSH,ACK -m length --length 52 -m state --state ESTABLISHED -j DROP
It does it's job for blocking the ...
1
vote
1answer
2k views
iptables connlimit: exclude multiple IP addresses
I have currently this IPTABLES command:
iptables -A INPUT -s ! 192.168.0.2 -p tcp --syn -m connlimit [...] -j DROP
As far as I know, such rule limit some number of connections following various ...
1
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0answers
63 views
Split TCP packet - Data layer vs IPv4Layer
What is the different between split TCP packet in the Data layer compare to split the packet in IPv4Layer ?
0
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2answers
796 views
How to redirect a packet with iptables that match a certain pattern? (eg a QUERY command with UDP)
I have a certain packet that I want at all times to be redirected to a specific ip on my virtual network interface. As for now my iptables is setup like this:
(the commands, I use \ as for now to ...
0
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1answer
198 views
How many times does switch calculates FCS?
Does a switch calculate the Frame check sequence (FCS) before sending packets? Because packet shouldn't change, so FCS should also stay the same.
-2
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1answer
90 views
How many data packets does it take to log in to facebook? [closed]
I want to find out how many packets are sent when visiting a site on the web. What's a good program that would help me get this kind of data?
0
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1answer
33 views
See historical packet receipt statistics in Windows
I know this is a long shot, but it would be really useful to me right now.
Does anyone know of a Windows function or 3rd party tool that can show stats about the receipt of packets on a network ...
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4answers
248 views
Is there anyway to tell what user will receive data from inbound packet?
In linux, considering this use case:
1. User initiates http request for webpage to remote server
2. Remote server answers request and sends packets
Is there any reference to the user who started ...
-1
votes
1answer
2k views
Set udp packet size limit
I have a CentOS server with a JAVA application that receive UDP data packets, it works all OK until the packet is bigger than 584 bytes, I read something about and seems to be a limit of UDP protocol.
...
0
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1answer
718 views
tcpdump show strange packet with incorrect src ip and dst ip
I have private LAN with > 100 servers, in which, I have 3 server:
x.x.x.37: run memcache on port 11211 (called s37 for short)
x.x.x.241: run an application server, which connect to memcache on
x.x.x....
2
votes
1answer
3k views
PF: Block all, but one subnet firewall rule?
I'm trying to do something that I thought would be relatively simple: Block all the traffic to a test server, other than my company's subnet.
I've tried things along these lines (111.111.0.0 is my ...
1
vote
1answer
5k views
TCP Sequence & Acknowledgment numbers
I have looked through other questions on here involving the relevant topics, but I am still not clear on this.
I have just been reading this explanation of TCP sequence & acknowledgment numbers.
...
2
votes
3answers
403 views
Is TCP header the same as TCP segment?
So, is a TCP header actually the same thing as a TCP segment? I was reading this page,
where it reads near the end that:
Even though it might seem they are, in most cases, when referring to
the ...
1
vote
1answer
152 views
Viewing the packet-size of an incoming IP
I have been looking for a sulution to this for a few hours. after no avail im asking for help here.
I need to watch my incoming packets by Size. in a format similar to:
IP SIZE
I have tried TCPDUMP ...
0
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3answers
2k views
How many packets will it take to send particular data?
If I know the maximum packet size is 1500 bytes say for Ethernet frame v2 then for example I want to transfer 1 KB over the Internet which is roughly 1024 bytes.
Will the packet be split into many ...
1
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1answer
140 views
Understanding ARP traces during OS load
Consider the following ARP packets captured while a unix machine was booting.
From the packets I understand that this machine whose MAC address is 00:22:22:22:22:22 is requesting information about ...
1
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2answers
218 views
Server sending packets every 5 minutes to 3 IPs
Been noticing in our firewall logs that three connections are being constantly established every 5 minutes from our web server and trying to send a packet to destination port 43 (whois port) cycling ...
1
vote
1answer
2k views
UDP maximum segment size
Environment:
I am writing a UDP client-server application. the path MTU between client and server is 1500 bytes (with only a wireless link between them, so this value is pretty much stable). My system ...
12
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1answer
17k views
Why is the “don't fragment” flag set in https and ssh protocols?
I've found a lot of information specifying that this is the case, however, I am really looking for the reason behind this. Why is it necessary? Is it necessary?
0
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1answer
46 views
forwarding of small and large packets: any difference?
When it comes to simple forwarding of packets (no errors being generated), are packets processed faster by routers when they are small as opposed to when they contain a large payload?
Or do routers ...
2
votes
0answers
320 views
Redhat 6.4 configured to log Martian packets but is not logging ll header
I am trying to investigate the source of martian packets I have been seeing on several servers connected to the same subnet. The logging of martian packets has been enabled in /etc/sysctl.conf.
...
6
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3answers
69k views
Excessive 'TCP Dup ACK' & 'TCP Fast Retransmission' causing issues on network. What's causing this?
I'm getting excessive TCP Dup ACK and TCP Fast Retransmission on our network when I transfer files over the MetroEthernet link. The two sites are connected by one sonicwall router, so the sites are ...
-1
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1answer
114 views
How do routers manage multiple data streams? [closed]
Routers manage data connections between the internet and computers or connections between computers on a LAN. It makes sense that when, for example, a computer requests music from Pandora, that ...
2
votes
1answer
2k views
10GbE be2net low pktgen performance
I am testing the network performance of two workstations, each having 2.4GHz Xeon quad core processors and NC550SFP PCIe Dual Port 10GbE Server Adapters, linked back to back.
I've checked the ...
0
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1answer
3k views
Dropping Packets Randomly
I have a SuperMicro Server based on the X9DR3-LN4F+ motherboard from SuperMicro. Original intentions for the system were quite different from what it has ended up serving, but that happens.
It is ...
0
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1answer
1k views
What does a packet capture in pfsense do?
I have some issues with a third party to establish a VPN connection. To debug it, I made a packet capture on the device that represents our synchronous DSL line. The solution I'm using is an old ...
0
votes
1answer
572 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
2answers
718 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 ?
...
2
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4answers
11k 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 ...
2
votes
2answers
5k 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 ...
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2answers
309 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
3k 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 ...
