The tag has no wiki summary.

learn more… | top users | synonyms

0
votes
2answers
41 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
votes
0answers
34 views

packet is not being forwarded from tap interface to bridge

I am running fedora 19 on a virtual machine and have two tap interfaces (A, B) created. I'd like to be able to send packet from A to B. I am trying to do this using a bridge, however with the bridge ...
0
votes
1answer
41 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.
0
votes
0answers
27 views

Bonding connection or other techniques to improve UDP delivery

I have several VOIP servers linked by heavily loaded connections, and the voice quality gets pretty spotty at times. I have setup QoS to ensure upstream bandwidth is allocated favorably for VOIP, ...
-2
votes
1answer
49 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
votes
1answer
20 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 ...
-1
votes
4answers
229 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 ...
0
votes
1answer
192 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
votes
1answer
104 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 ...
1
vote
1answer
376 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 ...
0
votes
1answer
646 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. ...
1
vote
3answers
170 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 ...
0
votes
0answers
46 views

Need to setup an intermediary to accept, alter and resend a UDP packet

Currently ApplicationA on ServerA sends a UDP packet to ApplicationZ on ServerZ several times throughout the day based on several triggers. The problem is that some of the data in that packet is sent ...
1
vote
1answer
45 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 ...
0
votes
0answers
14 views

How to route packets from a service (media service) based on the UID of the app that is using media service using IPTABLES

I am redirecting application packets through different PDN's based on their UID's (Process ID's) using IPtables. So my App1 is using PDN1 for its data transmission. and App2 is using PDN2 for its ...
0
votes
3answers
90 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
vote
1answer
62 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 ...
0
votes
1answer
101 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
387 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 ...
7
votes
1answer
1k 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
votes
0answers
168 views

Remove information revealed in packet inspection

I did a security scan of my server and got the following message: This test gives some information about the remote HTTP protocol - the version used, whether HTTP Keep-Alive and HTTP pipelining are ...
0
votes
1answer
33 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
138 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. ...
2
votes
3answers
13k 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
votes
1answer
74 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
802 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
votes
1answer
610 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
votes
1answer
337 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
150 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
117 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 ? ...
1
vote
4answers
2k 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
399 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
146 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
1k 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
4k 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
1k 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 ...
4
votes
1answer
3k 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
669 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 ...
1
vote
0answers
1k 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
359 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
573 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
110 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
247 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 ...
5
votes
2answers
3k 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
2k 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
189 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 ...
12
votes
1answer
10k 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 ...
4
votes
1answer
830 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
105 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
262 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, ...