0
votes
0answers
52 views

opensips sever running fine and UDP connection cannot register but TCP connections works fine

Im a newbie to opensips and Centos/Linux. Recently installed opensips sever which running smoothly on TCP connections, but users cannot register on UDP connections. here my Log, have a look. Feb 26 ...
3
votes
1answer
582 views

Reverse proxy for mixed tcp, udp, and http services

I'm building an architecture that will be hosting various services which individually maybe listening on a variable number of ports that could be mixed protocols. I want to map these services to ...
0
votes
0answers
114 views

How to forward UDP and TCP traffic from one IP to another

I have a server with two LAN cards installed. I have one server in U.S and one in India. I have created a GRE tunnel to route all traffic from the U.S Server to my Indian Server. My traffic has ...
23
votes
5answers
2k views

Can TCP and UDP packets be split into pieces?

Can TCP packets arrive to receiver by pieces? For example, if I send 20 bytes using TCP protocol, can I be 100% sure that I will receive exactly 20 bytes at once, not 10 bytes then another 10 bytes ...
2
votes
2answers
97 views

Minimal size of TCP communication

I am sending small amounts of data (up to 100 bytes) every 10 minutes from devices to TCP server. In my case overhead seems to be huge (we pay for each byte). I found that I have at least 7-10 packets ...
-6
votes
1answer
48 views

How to host a TCP / UDP service on the Internet which is currently running on my local machine? [closed]

I have created a TCP server and it's currently hosted on my local machine, but I want to host it on Internet like we host websites. Is there any company which provides this service? And what's the ...
1
vote
2answers
2k views

Reduce firewall rules by half - one iptables rule for tcp and udp

I have a number of iptables rules on my firewall that look like this: iptables -A zone_lan_forward -p tcp -d 1.2.3.0/24 -j ACCEPT iptables -A zone_lan_forward -p udp -d 1.2.3.0/24 -j ACCEPT Is ...
2
votes
1answer
354 views

How to force use of tcp instead of udp for rpcbind?

I'm trying to use tcp/111 for rpcbind under Debian Wheezy instead of udp/111. The portmap in Squeeze uses tcp/111 without any special configuration, but Wheezy fails. Even numerous sites (as well as ...
1
vote
2answers
236 views

TCP vs UDP Error-Checking

I've bounced upon two articles that describe in-depth on how TCP and UDP connections work. However there is some kind of inconsistency. Where one article tells me that UDP does no Error-Checking at ...
2
votes
2answers
1k views

Traceroute, ICMP, UDP and TCP

When does traceroute use TCP? Or does it just use UDP, also why does Traceroute use UDP on MacX and ICMP on windows? I thought ICMP just contains a message saying what caused the error of a packet and ...
1
vote
1answer
234 views

UDP packets dropped

A host sends UDP broadcast, but its UDP packets are not received by any other hosts in the same subnet. However, its TCP traffic with others hosts are OK. I observed this using tcpdump. Could it ...
1
vote
1answer
944 views

openvpn tcp or udp (specific situation, reliability-layer collisions)

My question is whether to use TCP of UDP for my openVPN connection. I've set up a simple network for a startup company that allows users from the outside to acces the network via an openvpn server (in ...
0
votes
3answers
3k views

Why is UDP slower than TCP on Ubuntu Server?

I transfer data between two Ubuntu Servers (12.04) via iperf on 1Gb LAN. iperf -s <-> iperf -c <addr> -n2G TCP speed = 925 Mbits/sec iperf -su <-> iperf ...
4
votes
1answer
564 views

HTTP, TCP, UDP and connectionless

I am a bit confused with HTTP lately. Some facts are that TCP can operate connection orientated or connectionless, this I understand. TCP though is connection-oriented while UDP is connectionless ...
1
vote
1answer
341 views

Does hole punching require a UDP rendezvous server Or could it be a TCP one?

I'm trying to get my head wrap around this issue... I would like to connect two users... Those users are already connected to a TCP server, which is aware of both public ip and connection TCP port. ...
17
votes
2answers
6k views

What is the “in-the-wire” size of a ethernet frame? 1518 or 1542?

According to the table here, it says that MTU = 1500 bytes and that the payload part is 1500 - 42 bytes or 1458 bytes (<- this is actually wrong!). Now on top of that you have to add IPv4 and UDP ...
2
votes
2answers
2k views

Can I test broadcast packets on a single machine?

I want to have a server sending broadcast UDP packets and two other clients, in the same machine, receiving them. Can I do that somehow? What IP address would I use? @gravyface gave me hope but I ...
2
votes
1answer
1k views

Block all incoming DNS requests EXCEPT from IPs x,y,

I want to block all incoming requests on my two DNS servers APART FROM certain IP addresses e.g. IP of 1.2.3.4 will be allowed to make requests but NOBODY else will. How do you do this with iptables? ...
0
votes
1answer
230 views

Very strange localhost connections on linux workstation. Need help identifiying the source

The following is the output of netstat on a Ubuntu machine. Can someone help decrypt the output? I am especially curious what the ::1:43213 connection is. Also, why are there so many connections ...
0
votes
2answers
318 views

TCP what's the purpose of the third step of 3-way-handshake [duplicate]

Possible Duplicate: Why is it 3-way-handshake and not more? Example: If a client wants to talk to a server, it just tells the server that it wants to establish a connection, then the server ...
2
votes
3answers
866 views

Why is it 3-way-handshake and not more?

TCP uses the 3-way-handshake mechanism. I understand how it works pretty well but I wonder why it's not 4, or even 5-way? Is it because that's too much overhead and is not needed?
2
votes
1answer
404 views

What is the difference between bind, network (interface) and multicast addresses?

The DatagramSocketImpl in Java has a joinGroup method that takes a socket address (IP and PORT) plus the interface address (IP and PORT). I am trying to understand the difference and purpose of each ...
1
vote
2answers
546 views

Https tunnel for carrying TCP and UDP packets

I had an issue with running Openvpn over UDP in my college network. The firewall was dropping UDP connections. As http and https were working fine and assuming that the firewall was inspecting packet ...
0
votes
1answer
580 views

Is there any way to set PPTP on UDP Protocol? [closed]

In our network,many web site has been filtered ,so we should use VPN or Socks ,They reduce any tcp connection speed by dropping random packet (Than post and get on http),So ssh,pptp and ... are so ...
1
vote
1answer
330 views

ICMP destination unreachable

I am working on an arch linux machine with ethernet interface eth1. I have created interface eth1:0 using ifconfig and given it a dummy hw address (00:01:02:03:04:05). When I send a UDP packet to a ...
0
votes
2answers
56 views

Listing TCP/UDP process from an organically grown application

I've been asked to compile a list of TCP/UDP and ports they use for the collection of application that comprise our product for a client who wants the information for their firewall. So I fired up ...
0
votes
2answers
874 views

How to optimize TCP / IP stack in Linux? [closed]

Currently I noticed there are about 15K open connections to localhost. It is mainly connecting to Memcached. I am clueless where I should start to optimize TCP/IP stack. Memcached support UDP, but ...
3
votes
2answers
193 views

Port Knocking and TCP/IP within the OSI model

I have read that Port Knocking can be subject to false negative (type II error) due to the optimization techniques of TCP/IP. A correct port knock given by the client may be read as incorrect by the ...
0
votes
1answer
686 views

how to enable port 7777

I am initiating file transfer using tcp on openfire server. But I am not able to open the port number 7777, from which I need to send files. I changed the security setting in the admin console panel ...
2
votes
1answer
795 views

Adding more than one IP to sip.conf tcpbindaddr and udpbindaddr (Asterisk 1.8)

The defaults in the sample sip.conf under Asterisk1.8 contain udpbindaddr=0.0.0.0 and tcpbindaddr=0.0.0.0. I want to bind the incoming [foo] extension to udp:192.168.1.1/255.255.255.0, the outgoing ...
0
votes
2answers
704 views

UDP over TCP on vpn connections

For example we have a VPN TCP transport connection through proxy. I wonder how is UDP emulated over this TCP connection? How its unreliable nature is emulated?
0
votes
3answers
336 views

Can a network interface be configured to have a default gateway for UDP packets?

It is quite possible that my question may not make a lot of sense. I apologize, but I am not a networking guy, and that's my excuse. To elaborate, WikiPedia defines "Default Gateway" as a node on a ...
0
votes
1answer
6k views

DNS SERVFAIL and Incorrect Flag only via TCP: Broken DNS Servers?

Is it poor configuration to return the root name servers in the additional section for a CNAME lookup that points to another domain? Particularly the one I'm seeing this with is a CNAME hosted by ...
0
votes
2answers
291 views

Make bridge table with UDP packet

Assume that all bridge table was empty (or at least don't have source and destination of my connection ) and want to update their bridge table with my sending packet (when I send packet all bridge ...
1
vote
1answer
297 views

Determine the Ports reserved and what service reserved them in Windows XP/2003

this question is always rise. How can i know what ports are currently reserved in windows XP/2003 and what service had reserved them. for example when i want to install Apache, default port will be ...
10
votes
3answers
8k views

Sockets found by lsof but not by netstat

I have an application which is running out of file descriptors, apparently by opening sockets, but I can't find out exactly what these sockets do. These appear in the lsof output as java 9689 ...
0
votes
1answer
58 views

Sharepoint Ports

I am installing Sharepoint 2007 and I want users to be able to sign into it from outside. I need to know what ports do I need to open and do I need UDP or TCP or both?
1
vote
1answer
148 views

What does it mean that most dropped packets have a different incoming and outgoing port?

Over the weekend an internet-facing DI-624 router of mine was e-mailing me logs like crazy for some reason. Normally it's a few a day, but it was about one every few minutes instead. Analyzing the ...
4
votes
2answers
6k views

Should I use TCP or UDP to run a web server

I have just installed Apache web server on my computer. I have managed to use it locally (I can open index.php from my computer using my web browser). But I would like to make my web site available ...
14
votes
4answers
21k views

Does HTTPS use TCP or UDP?

Does HTTPS use TCP or UDP?
2
votes
1answer
297 views

Set Windows Firewall to Stateless?

Is there a way to "dumb down" the Windows Firewall on Win2003 or Win2008 from stateful to "stateless", and have it only do basic port filtering on the public interface? If not, is there a simple, ...
2
votes
2answers
246 views

Can IP spoofed traffic get above the transport layer?

I'd like to know whether you could get packets with a spoofed IP address above the transport layer. My thoughts are: TCP: No, as acknowledgements would never get to the original sender if their IP ...
2
votes
2answers
8k views

What is the default TCP window size on Windows Server 2008?

What is the TCP (and UDP) default window size on Windows Server 2008? I think it's 1480 bytes, but I'm not sure. Can it be changed? How?
31
votes
11answers
21k views

What is the difference between UDP and TCP?

My router has two protocols (and a "both" option) that I can select when setting up port forwarding: UDP and TCP. What is the difference between these two protocols and when would you select one over ...