EzDevInfo.com

Change from IPv4 to IPv6: What are its effects on web development?

Do web developers need to be concerned by the end of IPv4? Or is this strictly a hosting level concern?

What can the average PHP/JavaScript/Ajax etc. developer do to mitigate the impact of the changeover?

Discuss!

(if this has come up before I apologies, but my search revealed nothing)

How to convert an IPv4 address into a integer in C#?

I'm looking for a function that will convert a standard IPv4 address into an Integer. Bonus points available for a function that will do the opposite.

Solution should be in C#.

ipv4.fiddler, how does it work?

I'm curious as to how fiddler is able to capture traffic when you use the URL ipv4.fiddler. Is ipv4 a special domain that resolves local and fiddler just registers with http.sys to proxy the call?

Any insight would be great.

Getting the private ip address of an Rook/Shiny page user

I have created some web app using Rook which listen to my network ip (192.168.xx.xx) at port 8000. Everyone inside my office can connect to them just typing http://192.168.xx.xx:8000/page_name in the browser. I need to monitor these pages usage and wonder how I can get the network ip address of those connected to them.

I'm not experienced in web development and from the research done so far it seems that using client side code like JavaScript it's very difficult (almost impossible) to achieve that, (correct me if I'm wrong). So, my question is: is there any way of getting the network client ip using server side code inside an Rook application? (If needed I'd be willing to change the web server, any solution appreciated).

Thanks and sorry in advance should my question seem confusing... in particular I'm unsure if other tags are needed.

EDIT: I would also accept answers using something different than Rook (but still in R)

EDIT 2: I have set Shiny Server following this link. I'm at step of configuring the Server in order to get the access_log that, according to @Thell, contains the information I need. In The shiny-server.conf I have added the relative statement and now is:

run_as shiny;

server {
  listen 3838;

  location / {
    site_dir /var/shiny-server/www;
    log_dir /var/shiny-server/log;
    directory_index on;
  }

}

access_log /home/michelec/log.txt;

the last line should tell shiny to write the access_log into my home folder. Nothing happens however, the log remains blank. according to here, in the Formats section, I should receive one of these logs:

default ':remote-addr - - [:date] ":method :url HTTP/:http-version" :status :res[content-length] ":referrer" ":user-agent"'
short ':remote-addr - :method :url HTTP/:http-version :status :res[content-length] - :response-time ms'
tiny ':method :url :status :res[content-length] - :response-time ms'
dev concise output colored by response status for development use

depending if you leave the default format or you change it.

Geolocation with IPv6?

I'm working on an IP geolocation library that uses the first three octets of an IPv4 address to determine a user's country, city, lat, lon, etc. Works like a charm.

But it doesn't handle IPv6 addresses, and I'd like it to do so.

Is there any way to transform an IPv6 address to get the equivalent of the first three octets of an IPv4 address, or are they on an entirely different numbering scheme, requiring a completely different ipgeo mapping?

Get destination address of a received UDP packet

Upon receiving a UDP packet, I need to respond to the sender with the address he used to send the packet to which I'm replying.

The recvfrom call lets me get the address of the sender, but how do I get the destination address of the received packet, which should match the address of one of the local host's interfaces?

Different browsers, different IPs?

I'm saving the user's IP addresses by saving the value of $_SERVER['REMOTE_ADDR'] in a MySQL database. Problem is that for both Firefox and Chrome $_SERVER['REMOTE_ADDR'] is ::1 (that means localhost in IPv6) and for IE and Opera is 127.0.0.1 (IPv4).

So, my questions are

• Are IP versions browser-dependant? (I used to think it depended on the computer)

• Should I create two fields in the database, one for IPv4 addresses and one for IPv6 ones?

• Should I unify all IPs to IPv6? And how can I do this in PHP (if it's even possible)?

API for configuring static IP addresses in an Android application

Is it possible to set the IP address of an interface in Android within an application?

I can query the available interfaces and their current addresses using java.net.NetworkInterface, but this doesn't provide a facility to change these. Did I just miss something somewhere, or is it not allowed?

I was hoping to be able to make my application either change or add an alias to one or more of the existing interfaces at runtime on an "off the shelf" device. (2.1/2.2). Ideally I'd like to do this for both IPv4 and IPv6 addresses.

Why does IPAddress.MapToIPv4() throw ArgumentOutOfRangeException?

This code throws an ArgumentOutOfRangeException on the last line

var initAddress = IPAddress.Parse("1.65.128.190");
var ipv6Address = initAddress.MapToIPv6();
Assert.IsTrue(ipv6Address.IsIPv4MappedToIPv6);
var ipv4Address = ipv6Address.MapToIPv4();

Can anyone explain why MapToIPv6() and MapToIPv4() are not round trip compatible?

edit: The exception originates from the IPAddress constructor, called by MapToIPv4().

Also, when the first line is

var initAddress = IPAddress.Parse("1.65.128.90");

no exceptions are thrown anymore

edit2: as @Luaan reproduced this, I added the tag [bug-reporting]. Also added [bcl]. Let's see if any MS personnel tracks those tags :)

edit3: reported at Connect https://connect.microsoft.com/VisualStudio/feedback/details/871964

List of possible internal socket statuses from /proc

I would like to know the possible values of st column in /proc/net/tcp. I think the st column equates to STATE column from netstat(8) or ss(8).

I have managed to identify three codes:

sl  local_address rem_address   st tx_queue rx_queue tr tm->when retrnsmt   uid  timeout inode
0: 0100007F:08A0 00000000:0000 0A 00000000:00000000 00:00000000 00000000     0        0 7321 1 ffff81002f449980 3000 0 0 2 -1                     
1: 00000000:006F 00000000:0000 0A 00000000:00000000 00:00000000 00000000     0        0 6656 1 ffff81003a30c080 3000 0 0 2 -1                     
2: 00000000:0272 00000000:0000 0A 00000000:00000000 00:00000000 00000000     0        0 6733 1 ffff81003a30c6c0 3000 0 0 2 -1                     
3: 0100007F:0277 00000000:0000 0A 00000000:00000000 00:00000000 00000000     0        0 7411 1 ffff81002f448d00 3000 0 0 2 -1                     
4: 0100007F:0019 00000000:0000 0A 00000000:00000000 00:00000000 00000000     0        0 7520 1 ffff81002f4486c0 3000 0 0 2 -1                     
5: 0100007F:089F 00000000:0000 0A 00000000:00000000 00:00000000 00000000     0        0 7339 1 ffff81002f449340 3000 0 0 2 -1           
6: 0100007F:E753 0100007F:0016 01 00000000:00000000 02:000AFA92 00000000   500        0 18198 2 ffff81002f448080 204 40 20 2 -1                   
7: 0100007F:E752 0100007F:0016 06 00000000:00000000 03:000005EC 00000000     0        0 0 2 ffff81000805dc00                                      

The above shows:

• On line sl 0: a listening port on tcp/2208. st = 0A = LISTEN
• On line s1 6: An established session on tcp/22. st = 01 = ESTABLISHED
• On line sl 7: An socket in TIME_WAIT state after ssh logout. No inode. st = 06 = TIME_WAIT

Can anyone expand on this list? The proc(5) manpage is quite terse on the subject stating:

   /proc/net/tcp
          Holds a dump of the TCP socket table. Much of the information is not of use apart from debugging. The "sl" value is the kernel hash slot for the socket, the "local address" is  the  local  address  and
          port  number pair.  The "remote address" is the remote address and port number pair (if connected). ’St’ is the internal status of the socket.  The ’tx_queue’ and ’rx_queue’ are the outgoing and incom-
          ing data queue in terms of kernel memory usage.  The "tr", "tm->when", and "rexmits" fields hold internal information of the kernel socket state and are only useful  for  debugging.   The  "uid"  field
          holds the effective UID of the creator of the socket.

And on a related note, the above /proc/net/tcp output is showing a few listening processes (2208, 62, 111 etc). However, I cannot see a listening tcp connection on tcp/22, althought the established and time_wait states are shown. Yes, I can see them in /proc/net/tcp6 but should they not be present in /proc/net/tcp also? Netstat output shows it differently to applications bound only to ipv4. E.g.

tcp        0      0 0.0.0.0:111                 0.0.0.0:*                   LISTEN      4231/portmap        
tcp        0      0 :::22                       :::*                        LISTEN      4556/sshd           

Many thanks, -Andrew

How do I determine the local host’s IPv4 addresses?

How do I get only Internet Protocol version 4 addresses from Dns.GetHostAddresses()? I have the code below, and it gives me IPv4 and IPv6 addresses. I have to make it work with boxes that have multiple IPv4 addresses.

IPAddress[] localIPs = Dns.GetHostAddresses(Dns.GetHostName());
private void get_IPs()
    {
        foreach (IPAddress a in localIPs)
        {
           server_ip = server_ip + a.ToString() + "/";
        }
    }

Representing IPv4/IPv6 addresses in Oracle

In Oracle, what is the appropriate data type or technique for representing network addresses, which addresses may be IPv4 or IPv6?

Background: I'm converting a table recording network activity, built using the PostgreSQL inet data type to hold both v4 and v6 addresses in the same table.

No row contains both v4 and v6 addresses, however. (That is, a record is either from a machine's v4 stack, or a machine's v6 stack.)

What is the total amount of public IPv4 addresses?

Yes, I am needing to know what the total number possible IPs in the public IPv4 space.

I'm not sure where to even get a neat list of all the IP address ranges, so could someone point me to a resource to calculate this myself or calculate the total number of IPs for me?

Also, by Public IPs I mean not counting reserved or private-range IP addresses.. Only the ones that can be access through the internet.

getaddrinfo and IPv6

I'm trying to understand what the getaddrinfo function returns :

#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netdb.h>

int main (int argc, char *argv[])
{


struct addrinfo *res = 0 ;

  getaddrinfo("localhost", NULL ,NULL,&res);
  printf("ai_flags -> %i\n", res->ai_flags) ;
  printf("ai_family -> %i\n", res->ai_family) ;
  printf("ai_socktype -> %i\n", res->ai_socktype) ;
  printf("ai_protocol -> %i\n", res->ai_protocol) ;
  printf("ai_addrlen -> %i\n", res->ai_addrlen) ;
  struct sockaddr_in* saddr = (struct sockaddr_in*)res->ai_addr;
  printf("ai_addr hostname ->  %s\n", inet_ntoa(saddr->sin_addr));

  freeaddrinfo(res);

  return 0 ;
}

results :

ai_flags -> 40
ai_family -> 2
ai_socktype -> 1
ai_protocol -> 6
ai_addrlen -> 16
ai_addr hostname ->  127.0.0.1

In /etc/hosts, I 've got :

127.0.0.1 localhost    
::1     localhost

Getaddrinfo returns only 127.0.0.1 and not ::1 ? I don't understand why ?

The second question is where can I find the meaning of those ints (40,2,1,6 etc) ? I've read the man but there is nothing about that.

I also wanted to know if it's possible to give a IPv6 adress (for example ::1) and the function returns the name : localhost ?

Thanks a lot !!

Converting C++ TCP/IP applications from IPv4 to IPv6. Difficult? Worth the trouble?

Over the years I've developed a small mass of C++ server/client applications for Windows using WinSock (Routers, Web/Mail/FTP Servers, etc... etc...).

I’m starting to think more and more of creating an IPv6 version of these applications (While maintaining the original IPv4 version as well, of course).

Questions:

1. What pitfalls might I run into?
2. Is the porting/conversion difficult?
3. Is the conversion worth it?

For a reference (or for fun), you can sneek a peak of the IPv4 code at the core of my applications.