0
votes
1answer
20 views

Why am I seeing prefixed/duplicated packets coming from a comcast device?

I'm looking at traffic my CPE from Comcast in Wireshark, and for every packet, there is an additional packet that is the exact same, except for 4 additional bytes at the beginning of the frame ...
1
vote
1answer
53 views

Intermittent switch failure and data flooding, hardware capacity?

We are using a switch (ZIO-SW500) connected to the building main network and we suffers from intermittent network halt. Normally the network works well. But, sometimes traffic designated to other ...
0
votes
1answer
130 views

SIP INVITE packet has WAN address rather than call manager LAN IP

I am using SIP between two subnets (192.168.3.0/24 and 192.168.30.0/24) each connected via VPN. I have a call server on 192.168.3.100, and two phones 192.168.30.118 (Ext. 3128) and 192.168.30.119 ...
2
votes
2answers
141 views

Packets returning but traceroute fails

I get this output from traceroute: #traceroute -i eth1 -s 192.168.12.14 192.168.1.72 1 192.168.12.1 (192.168.12.1) 1.410 ms 2.076 ms 2.251 ms 2 * * * 3 * * * etc.. But in another terminal I ...
0
votes
0answers
42 views

ZyXel ES-2024 - Mirrored port showing duplicated traffic

I have a ZyXel ES-2024 PWD switch. I would like a computer plugged into port 26 to see all traffic that passes through port 2, both inbound and outbound. I have configured port mirroring for the ...
3
votes
1answer
179 views

Need help understanding capturing from Wireshark?

I am having issues with my FTP servers. Connecting, sending and receiving fail sometimes, and it is not consistent. I manage to capture and filter by IP the packets, I just need pointers on what can ...
1
vote
2answers
133 views

Can I capture ISP SNMP information with Wireshark?

I am trying to do some heavy digging into SNMP, BPI+, ISP networks. Since wireshark can be used to capture network data, would I be able to use it to remotely capture my ISP SNMP agent information and ...
2
votes
1answer
180 views

Strange Ethernet II packets in wireshark

Looking at a wireshark capture, I'm seeing something really strange. Ethernet II packets with random data are being sent on the network. The larger packets in the capture seem to contain bits and ...
0
votes
2answers
72 views

Occasional Delay on Website Resources: Packet Loss Due to Bandwidth Cap?

My website loads more slowly than I think it should, due to a few of the assets taking an absurdly long time to download from the server. I've been trying to track down the cause of this. I'm about ...
-6
votes
1answer
141 views

How to monitor all network traffic [closed]

I have installled wireshark on my server but can only monitor traffic through the local nic but all network traffic does not go through the server. I would like to monitor all network traffic. Are ...
1
vote
0answers
100 views

NFSv3 Asynchronous Write Depends on Block Size?

I am trying to figure out if my NFSv3 deployment is performing SAFE asynchronous writes. I suspect that it is doing strictly synchronous writes, as I am getting poor performance in general. I used ...
0
votes
1answer
114 views

How can I measure the cumulative network usage of a process, from execution beginning to end

I want to measure how much bandwidth git pull uses, preferably by prefixing git command with desired program, i.e. nettally git pull Alternatively, is there some sneaky way to accumulate nethogs / ...
1
vote
1answer
66 views

Wireshark not found after installing RHEL 5.5 [closed]

After installing Wireshark in RHEL 5.5 (32bit) with following command: yum install wireshark Wireshark not found: [root@localhost ~]# wireshark bash: wireshark: command not found What ...
0
votes
1answer
77 views

tshark duration of a conversation for a ip address

i can retrieve the follow info from a .pcap : ================================================================================ IPv4 Conversations Filter:ip.addr==1xx.1xx.0.1xx ...
0
votes
3answers
2k views

Can Wireshark capture an entire Ethernet frame including preamble, CRC and Interframe spacing?

I am examining an Ethernet frame in Wireshark. According to the "Ethernet frame" Wikipedia article and accompanying diagrams, "A frame starts with a 7-octet preamble and 1-octet start frame delimiter ...
2
votes
1answer
2k views

tcpdump capturing tcp resets by host

I am trying to figure out where my tcp resets on my webserver happen. I have the following capture: tcpdump -fnni bond0:-nnvvS -w dump.pcap 'tcp[tcpflags] & (tcp-rst) !=0' When I look at the ...
2
votes
3answers
601 views

While analyzing a network interface using WireShark, which device's timestamp is recorded?

OK, this may seem trivial but due to the nature of testing required for my application, I need to get precise timestamps. I am using WireShark to analyze packets. Suppose I have a network with 2 ...
4
votes
3answers
1k views

Wireshark running on a server seeing lots of `ARP who has` with different tells

We're seeing some suspicious network activity, and when I was trying to see if it was one particular server of ours I ran a Wireshark trace. I noted a lot of ARP packets asking who has x.x.x.x, but ...
-3
votes
2answers
641 views

Alternatives to wireshark? [closed]

What would be a good option to troubleshoot an interaction of browser with a server besides wireshark? I mean being able to see what the browser sends and receives. Is firebug a good alternative or is ...
0
votes
1answer
47 views

Is there an app that can provide details about wifi access point config?

I'm wondering if there is an easier way to determine of the following parameters of a wifi network. For users who already have say a laptop connected to a wifi network. Does wifi network support ...
1
vote
2answers
983 views

TCPDump and IPTables DROP by string

by using tcpdump -nlASX -s 0 -vvv port 80 I get something like: 14:58:55.121160 IP (tos 0x0, ttl 64, id 49764, offset 0, flags [DF], proto TCP (6), length 1480) 206.72.206.58.http > ...
0
votes
0answers
389 views

How to interpret findings on TCP Send/Recv Buffers

I have an application running on a CentOS machine that connects to a remote DB server on another CentOS machine. Every once in a while, without any discernable warning signs, the application seems to ...
2
votes
2answers
151 views

Is TCP RWIN set by application or OS?

I have a situation where an application is listening on a TCP port and every once in a while, as seen in tcp dumps, gets its Receiving Window (RWIN) set to zero. When this happens, its Recv-Q stops ...
-2
votes
2answers
620 views

Using tcpdump to find strings [closed]

I need to block certain TCP packets by trying to find a string match in and on them. Is there a way to do that with TCPDump? Or do I need wireshare install on my linux server? One I have the string ...
-1
votes
1answer
82 views

Wireshark not displaying GET or POST data [closed]

I'm a student and I'm taking my first networking class. I'm working on an assignment designed to get me used to using Wireshark and understanding packet transfers. Part of the assignment is to collect ...
3
votes
1answer
226 views

How to use a switch as a network tap?

I would like to tcpdump all traffic that my router does when it makes a firmware update. So I have taken a HP ProCurve 1800-8G switch and mirrored port 7 to port 8. I have connected: Internet ...
3
votes
2answers
220 views

What are cables/boxes called for listening in on a RJ45 cable?

I would like to capture the traffic from a router, so I assume there must exist a cable or hardware box with 3 RJ45 socks, where two of them are IN and OUT, and the third is for capturing device (a ...
3
votes
2answers
1k views

How to use Linux to capture packets on eth0 and send everything to eth1?

Today I got an enterprise Internet connection together with a Sagemcom router. The first time it is connected to the Internet, it will spend 20 minutes upgrading the firmware. I would really like to ...
0
votes
3answers
460 views

Wireshark Promiscuous Mode and multiple Subnets

Is it possible to Sniff traffic with Wireshark where the source IP and Destination IP are on different subnets (of the same network) and neither of them are your IP? NIC is Intel 82579LM.
5
votes
2answers
390 views

Is it possible for Wireshark to drop packets purposely?

I would like to test something like VoIP. I would like to test with some "artificial packet loss". Is Wireshark able to do this? Or is there any good solutions?
2
votes
2answers
1k views

using wireshark/tshark in command line to ignore ssh connections

I'm trying to debug some by looking at the packets and I would like to avoid getting all the SSH traffic to the server. Is there a way to ignore? I tried to do something like tshark -f "port !22" but ...
2
votes
0answers
1k views

Issue with Netgear GS108T Managed Switch and Jumbo Frames

I recently purchased a Netgear GS108T managed switch and I am trying to configure jumbo packets between my NAS (Thecus N4100Pro), PC and managed switch. I should mention the fact that I was able to ...
2
votes
1answer
135 views

Printing to shared printers across VPN

I have a program that prints labels at five remote sites. Two sites, aren't working, but the rest are with an identical (as far as I can tell) setup. Using Wireshark, I have determined that the ...
2
votes
2answers
364 views

Network flooded with seemingly empty packets

Let me preface this with the fact that I'm just a web developer at my company with little networking knowledge. Earlier today there was a department that lost all of their network connections so I ...
-3
votes
1answer
96 views

Inspecting the E-mail traffic of a Windows Server 2008 R2 [closed]

I have seen that the IP address of my mail server has added to blocked IP address list on http://psbl.org. I am using this server for personal use. So, it is not that much of an issue that I am, as a ...
3
votes
1answer
219 views

How Wireshark could read data from other ips

When I open wireshark I could see the packets send by machines other than mine. How could its possible? Example 8252 99.150192 somoeneip 239.255.255.250 SSDP NOTIFY * HTTP/1.1 8253 ...
7
votes
2answers
2k views

tcpdump: snaplen set to 0 but still get “Packet size limited during capture”?

Due to this problem, I'm going to sniff some packets on the MySQL server backend to see what happens: # tcpdump -vv -s0 -c 100 -i bond0 tcp port 3306 and host 192.168.3.87 -w ...
1
vote
0answers
77 views

Divert TCP connection

I am trying to divert a TCP connection. Given a client (C) which is connected to a router R and two servers (S1 and S2) are connected to the router, C initially connects to S1. I am trying to write an ...
2
votes
1answer
437 views

Is Winpcap able to capture all packets going through a Gigabit NIC without missing any packets?

I want to use Winpcap to capture all network packets going through a Gigabit NIC of a server. Assuming that I am able to utilize the network link up to 100%, the maximum network speed is 1000Mbps. If ...
3
votes
3answers
1k views

TCP segments of an HTTP Request in wrong order

My web-services server sometimes does not receive correct HTTP requests and returns "500 - Internal Server Error". Using tcpdump and Wireshark on the server, I found out that HTTP requests are ...
2
votes
4answers
729 views

Extremely high arp fllooding from the router

My subnet is 10.162.0.0/16. We have a router with a couple of interfaces. Gateway for my subnet is 10.162.0.1. The router is situated in another building and I haven't direct access to it. Line from ...
3
votes
1answer
1k views

huge packet loss and checksum errors

Our 2008 server began to work very slowly within 2 weeks. Our web sites (iis 7.5) are loading very slowly and sometimes its freezing. We began testing with wireshark and saw that our packets are ...
0
votes
1answer
442 views

Router is continually broadcasting the same ARP request, with the exact contents

I hope the question is clear and that this is correct place to post the question. My router is broadcasting the same ARP frame over and over (once every second). It's probably not a big deal, but I ...
3
votes
2answers
537 views

How to separate PCAP by unique IP address

I have an hour long PCAP file which has about 60 individual network attacks done on our test network here at work. Each attack comes from a unique IP address which was not used elsewhere during the ...
0
votes
0answers
250 views

Packets dropped at endpoint NIC — Windows 2003

I have a virtualized Windows 2003 server that hosts one of my pieces of server software. The problem is that the port listener of this server doesn't get the client traffic sometimes. With Wireshark ...
4
votes
2answers
1k views

syn/ack sequence number confusion

I was looking at some random traffic in wireshark and came across this (using relative seq/ack numbers): 1. myIP -> 74.125.227.96 [SYN] seq=0 2. 74.125.227.96 -> myIP ...
0
votes
1answer
179 views

Communication problems on secondary interface tap0

I am using UDP over ipv6 as communication stack. I have network client running on secondary virtual interface tap0. It generates messages for server which is supposed to run on the same interface but ...
-1
votes
1answer
169 views

Measuring delays between various components on a localhost

I need to profile a web application from a system performance standpoint and find out for typical user actions (accessing the home page, logging in...) where the delay comes from. The website uses the ...
0
votes
2answers
663 views

How to use tshark to do this task

I don't have any base knowledge about tshark, and it is hard to find any tutorial to help me with this. So now I have a pcap file which consists a lot of network flows; a time range; an ip addr; a ...
0
votes
2answers
170 views

SYN packets sent from one server but never arrives at destination

I am troubleshooting network problems for a client, remotely. The problem they have is that they get "connection timed out" occasionally between a web server and and a back-end search server. They can ...