(Port forwarding done) now ipcam and enc28j60

You haven't exactly posted the whole sketch, so it's all guesswork really. But I doubt this is right:

static char baseurl[]="http://192.168.1.15/";

If you are generating forms, and that form is designed to respond to baseurl, then it will go back to the wrong address.

Also, what Arduino board are you using?

I use ENC28J60 the cheapest version of a real ethernet shield w5100 haha!

I try 192.168.1.15:85 but it do not work

The sketch I posted is only the ''ethernet'' part, the rest is to control ledpins. If you realy want i can show all my sketch.

Which Arduino are you using? Uno? Mega2560?

Yes, show the whole sketch.

Hanrun:
I use ENC28J60 the cheapest version of a real ethernet shield w5100 haha!

I try 192.168.1.15:85 but it do not work

The sketch I posted is only the ''ethernet'' part, the rest is to control ledpins. If you realy want i can show all my sketch.

192.168.1.15 is not an address that is routable on the internet. Your router/firewall will have a different IP address when seen from the outside internet. Thus, any form that references that address simply won't work from the outside.
Luckily, HTTP already defaults the base URL to whatever you used to get to the form in the first place. Thus, you can try changing the baseurl to simply "/" and it might have some chance of working, if I read that sketch right.
That is -- assuming you can get to the page in the first place, then posting the form should work if you set the baseurl to "/" rather than a specific protocol and address.

static uint8_t myip[4] = {192,168,1,15};
static char baseurl[]="http://mydomain.no-ip.com/";
static uint16_t mywwwport =85; // listen port for tcp/www (max range 1-254)

OR

static uint8_t myip[4] = {192,168,1,15};
static char baseurl[]="/";
static uint16_t mywwwport =85; // listen port for tcp/www (max range 1-254)

Duemilanove

#include "etherShield.h"


// please modify the following two lines. mac and ip have to be unique
// in your local area network. You can not have the same numbers in
// two devices:
static uint8_t mymac[6] = {0x54,0x55,0x58,0x10,0x00,0x24}; 
static uint8_t myip[4] = {192,168,1,15};
static char baseurl[]="http://192.168.1.15/";
static uint16_t mywwwport =85; // listen port for tcp/www (max range 1-254)



#define BUFFER_SIZE 1500
static uint8_t buf[BUFFER_SIZE+1];
#define STR_BUFFER_SIZE 200
static char strbuf[STR_BUFFER_SIZE+1];

EtherShield es=EtherShield();

// prepare the webpage by writing the data to the tcp send buffer
uint16_t print_webpage(uint8_t *buf, byte on_off1, byte on_off2, byte on_off3);
int8_t analyse_cmd(char *str);

// LED cathode connects the Pin4, anode to 5V through 1K resistor
#define LED_PIN4  4
#define LED_PIN5  5
#define LED_PIN6  6
    uint16_t plen, dat_p;
  int8_t cmd;
  byte on_off1 = 0;
  byte on_off2 = 0;
  byte on_off3 = 0;

void setup(){

   /*initialize enc28j60*/
	es.ES_enc28j60Init(mymac);
   es.ES_enc28j60clkout(2); // change clkout from 6.25MHz to 12.5MHz
   delay(10);
        
	/* Magjack leds configuration, see enc28j60 datasheet, page 11 */
	// LEDA=greed LEDB=yellow
	//
	// 0x880 is PHLCON LEDB=on, LEDA=on
	// enc28j60PhyWrite(PHLCON,0b0000 1000 1000 00 00);
	es.ES_enc28j60PhyWrite(PHLCON,0x880);
	delay(500);
	//
	// 0x990 is PHLCON LEDB=off, LEDA=off
	// enc28j60PhyWrite(PHLCON,0b0000 1001 1001 00 00);
	es.ES_enc28j60PhyWrite(PHLCON,0x990);
	delay(500);
	//
	// 0x880 is PHLCON LEDB=on, LEDA=on
	// enc28j60PhyWrite(PHLCON,0b0000 1000 1000 00 00);
	es.ES_enc28j60PhyWrite(PHLCON,0x880);
	delay(500);
	//
	// 0x990 is PHLCON LEDB=off, LEDA=off
	// enc28j60PhyWrite(PHLCON,0b0000 1001 1001 00 00);
	es.ES_enc28j60PhyWrite(PHLCON,0x990);
	delay(500);
	//
  // 0x476 is PHLCON LEDA=links status, LEDB=receive/transmit
  // enc28j60PhyWrite(PHLCON,0b0000 0100 0111 01 10);
  es.ES_enc28j60PhyWrite(PHLCON,0x476);
	delay(100);
        
  //init the ethernet/ip layer:
  es.ES_init_ip_arp_udp_tcp(mymac,myip,85);
  
 	pinMode(LED_PIN4, OUTPUT); 
 	digitalWrite(LED_PIN4, HIGH);  // switch off LED
        pinMode(LED_PIN5, OUTPUT); 
 	digitalWrite(LED_PIN5, HIGH);  // switch off LED
        pinMode(LED_PIN6, OUTPUT); 
 	digitalWrite(LED_PIN6, HIGH);  // switch off LED
}

void loop(){
 

  plen = es.ES_enc28j60PacketReceive(BUFFER_SIZE, buf);

	/*plen will ne unequal to zero if there is a valid packet (without crc error) */
  if(plen!=0){
	           
    // arp is broadcast if unknown but a host may also verify the mac address by sending it to a unicast address.
    if(es.ES_eth_type_is_arp_and_my_ip(buf,plen)){
      es.ES_make_arp_answer_from_request(buf);
      return;
    }

    // check if ip packets are for us:
    if(es.ES_eth_type_is_ip_and_my_ip(buf,plen)==0){
      return;
    }
    
    if(buf[IP_PROTO_P]==IP_PROTO_ICMP_V && buf[ICMP_TYPE_P]==ICMP_TYPE_ECHOREQUEST_V){
      es.ES_make_echo_reply_from_request(buf,plen);
      return;
    }
    
    // tcp port www start, compare only the lower byte
    if (buf[IP_PROTO_P]==IP_PROTO_TCP_V&&buf[TCP_DST_PORT_H_P]==0&&buf[TCP_DST_PORT_L_P]==mywwwport){
      if (buf[TCP_FLAGS_P] & TCP_FLAGS_SYN_V){
         es.ES_make_tcp_synack_from_syn(buf); // make_tcp_synack_from_syn does already send the syn,ack
         return;     
      }
      if (buf[TCP_FLAGS_P] & TCP_FLAGS_ACK_V){
        es.ES_init_len_info(buf); // init some data structures
        dat_p=es.ES_get_tcp_data_pointer();
        if (dat_p==0){ // we can possibly have no data, just ack:
          if (buf[TCP_FLAGS_P] & TCP_FLAGS_FIN_V){
            es.ES_make_tcp_ack_from_any(buf);
          }
          return;
        }
        if (strncmp("GET ",(char *)&(buf[dat_p]),4)!=0){

          	// head, post and other methods for possible status codes see:
            // http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html
            plen=es.ES_fill_tcp_data_p(buf,0,PSTR("HTTP/1.0 200 OK\r\nContent-Type: text/html\r\n\r\n<h1>200 OK</h1>"));
            goto SENDTCP;
        }
 	if (strncmp("/ ",(char *)&(buf[dat_p+4]),2)==0){
                plen=print_webpage(buf, on_off1, on_off2, on_off3);
            goto SENDTCP;
         }
        cmd=analyse_cmd((char *)&(buf[dat_p+5]));
        
        if (cmd==2){
                on_off1=1;
        	digitalWrite(LED_PIN4, LOW);  // switch on LED
        }
        else if (cmd==3){
                on_off1=0;
        	digitalWrite(LED_PIN4, HIGH);  // switch off LED
        }
        else if (cmd==4){
                on_off2=1;
        	digitalWrite(LED_PIN5, LOW);  // switch on LED
        }
        else if (cmd==5){
                on_off2=0;
        	digitalWrite(LED_PIN5, HIGH);  // switch off LED
        }
        
        else if (cmd==6){
                on_off3=1;
        	digitalWrite(LED_PIN6, LOW);  // switch on LED
        }
        else if (cmd==7){
                on_off3=0;
        	digitalWrite(LED_PIN6, HIGH);  // switch off LED
        }

        plen=print_webpage(buf, on_off1, on_off2, on_off3);
        	
        	   plen=print_webpage(buf, on_off1, on_off2, on_off3);

Next:

SENDTCP:  es.ES_make_tcp_ack_from_any(buf); // send ack for http get
           es.ES_make_tcp_ack_with_data(buf,plen); // send data       
      }
    }
  }
        
}
// The returned value is stored in the global var strbuf
uint8_t find_key_val(char *str,char *key)
{
        uint8_t found=0;
        uint8_t i=0;
        char *kp;
        kp=key;
        while(*str &&  *str!=' ' && found==0){
                if (*str == *kp){
                        kp++;
                        if (*kp == '\0'){
                                str++;
                                kp=key;
                                if (*str == '='){
                                        found=1;
                                }
                        }
                }else{
                        kp=key;
                }
                str++;
        }
        if (found==1){
                // copy the value to a buffer and terminate it with '\0'
                while(*str &&  *str!=' ' && *str!='&' && i<STR_BUFFER_SIZE){
                        strbuf[i]=*str;
                        i++;
                        str++;
                }
                strbuf[i]='\0';
        }
        return(found);
}

int8_t analyse_cmd(char *str)
{
        int8_t r=-1;
     
        if (find_key_val(str,"cmd")){
                if (*strbuf < 0x3a && *strbuf > 0x2f){
                        // is a ASCII number, return it
                        r=(*strbuf-0x30);
                }
        }
        return r;
}


uint16_t print_webpage(uint8_t *buf, byte on_off1, byte on_off2, byte  on_off3)
{

       int i=0;
    
        
        uint16_t plen;
        
 
        
        plen=es.ES_fill_tcp_data_p(buf,0,PSTR("HTTP/1.0 200 OK\r\nContent-Type: text/html\r\n\r\n"));
    plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<left>Arduino web server test</LEFT> "));
        plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<body bgcolor=\"#000000\"> "));
        plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<font color=\"#FFFFFF\"><FONT FACE=\"arial\"><RIGHT><I><FONT SIZE=1>BTCAD.<U> V1.0 beta</U></h1></FONT></FONT></I> </RIGHT> "));
        plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<FONT SIZE=3> <font color=\"#00FF00\"></h1><a href=\"http://192.168.1.1\">192.168.1.1<a></FONT></FONT>"));
    



            
   

        plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<hr>
<form METHOD=get action=\""));
        plen=es.ES_fill_tcp_data(buf,plen,baseurl);
        plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("\">"));
        plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<h2><font color=\"#FFFFFF\"> selection  </h2> "));
 				plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<h1><font color=\"#FFFFFF\"> "));
 
    
        

            
        
            
    
        

            if(on_off1)
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<img src=\"http://i915.photobucket.com/albums/ac357/mistermpss/test2on.gif\" >"));
        else 
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<img src=\"http://i915.photobucket.com/albums/ac357/mistermpss/test2off-1.gif\" >"));
        
 
        
        if(on_off1){
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<input type=hidden name=cmd value=3>"));
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<input type=submit value=\" #1 ON \"></form>"));
          }
         
        else {
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<input type=hidden name=cmd value=2>"));
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<input type=submit value=\" #1 OFF\"></form>"));
     }


          
        plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("
<form METHOD=get action=\""));
        plen=es.ES_fill_tcp_data(buf,plen,baseurl);
        plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("\">"));
 
        
            if(on_off2)
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<img src=\"http://i915.photobucket.com/albums/ac357/mistermpss/test2on.gif\" >"));
        else 
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<img src=\"http://i915.photobucket.com/albums/ac357/mistermpss/test2off-1.gif\" >"));
        

        if(on_off2){
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<input type=hidden name=cmd value=5>"));
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<input type=submit value=\" #2 ON\"></form>"));
        }
           
        else {
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<input type=hidden name=cmd value=4>"));
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<input type=submit value=\" #2 OFF\"></form>"));
         
         
             }
           
        plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("
<form METHOD=get action=\""));
        plen=es.ES_fill_tcp_data(buf,plen,baseurl);
        plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("\">"));
    
       
                if(on_off3)
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<img src=\"http://i915.photobucket.com/albums/ac357/mistermpss/test2on.gif\" >"));
        else 
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<img src=\"http://i915.photobucket.com/albums/ac357/mistermpss/test2off-1.gif\" >"));
        
  
        
        if(on_off3){
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<input type=hidden name=cmd value=7>"));
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<input type=submit value=\" #3 ON\"></form>"));
        }
        else  {
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<input type=hidden name=cmd value=6>"));
        	plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<input type=submit value=\" #3 OFF \"></form>"));
        }
        
        
                plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("  </font></h1>
 ") );
        
        plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("</CENTER><hr><hr><FONT FACE=\"arial\"><FONT SIZE=1>link:</font><FONT SIZE=5> <p> Testing <a href=\"http://www.google.com\">www.google.com<a></font></FONT>"));
  
        return(plen);
}

okay take a look on :

#include "etherShield.h"

// please modify the following two lines. mac and ip have to be unique
// in your local area network. You can not have the same numbers in
// two devices:
static uint8_t mymac[6] = {0x54,0x55,0x58,0x10,0x00,0x24};
static uint8_t myip[4] = {192,168,1,15};
static char baseurl[]="/";
static uint16_t mywwwport =85; // listen port for tcp/www (max range 1-254)

with this change, i can control trough the lan, not over internet.

...

I creat a DNS with my dhcp IP ex:

71.112.345.3 is now Mydomain.no-ip.com
I opened the port 85 both udp & tcp
I can acces my router from anywhere with : Mydomain.no-ip.com
but nothing work with http://mydomain.no-ip.com:85/

In "code" tags, not "quote" tags thanks. It makes it (almost) impossible to read. Edit those posts and change [ quote ] to [ code ] (leaving out the spaces).

Hanrun:
with this change, i can control trough the lan, not over internet.

OK, well through the internet, bring up the page in question in your web browser (the page that doesn't work). Now right-click and select "view page source" or whatever it is exactly. Copy that source and paste it here, inside code tags (select the text and hit the # button above the edit box in your browser).

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
 
    <head>
        <link rel="stylesheet" type="text/css" href="ErrorPageTemplate.css" >
 
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Internet Explorer ne peut pas afficher cette page Web</title>
 
        <script src="errorPageStrings.js" language="javascript" type="text/javascript">
        </script>
        <script src="httpErrorPagesScripts.js" language="javascript" type="text/javascript">
        </script>
    </head>
 
    <body onLoad="javascript:initMoreInfo('infoBlockID');">
 
        <table width="730" cellpadding="0" cellspacing="0" border="0">
 
        <!-- Error title -->
            <tr>
                <td id="infoIconAlign" width="60" align="left" valign="top" rowspan="2">
                    <img src="noConnect.png" id="infoIcon" alt="Info icon" width="48" height="48">
                </td>
                <td id="mainTitleAlign" valign="middle" align="left" width="*">
                    <h1 id="mainTitle">Internet Explorer ne peut pas afficher cette page Web</h1>
                </td>
            </tr>
 
            <tr>
                <!-- This row is for HTTP status code, as well as the divider-->
                <td id="errorCodeAlign" class="errorCodeAndDivider" align="right">&nbsp;
                    <div class="divider"></div>
                </td>
            </tr>
 
        <!-- What you can do -->
            <tr>
                <td>
                    &nbsp;
                </td>
                <td id="whatToTryAlign" valign="top" align="left">
                    <h2 id="whatToTry">Essayez la chose suivante :</h2>
                </td>
            </tr>
 
        <!-- Check Connection -->
            <tr>
                <td >
                    &nbsp;
                </td>
                <td id="checkConnectionAlign" align="left" valign="middle">
                    <h4>
                        <table>
                            <tr>
                                <td valign="top">
                                </td>
                                <td valign="middle">
                                    <button onclick="javascript:diagnoseConnectionAndRefresh(); return false;" id="diagnose">Diagnostiquer les problèmes de connexion</button>
                                </td>
                            </tr>
                        </table>
                    </h4>
                </td>
            </tr>
 
 
        <!-- InfoBlock -->
            <tr>
                <td id="infoBlockAlign" align="right" valign="top">
                    &nbsp;
                </td>
                <td id="moreInformationAlign" align="left" valign="middle">
                    <h4>
                      <table>
                          <tr>
                              <td valign="top">
                                  <a href="#" onclick="javascript:expandCollapse('infoBlockID', true); return false;"><img src="down.png" id="infoBlockIDImage" border="0" class="actionIcon" alt="Informations"></a>
                              </td>
                              <td valign="top">
                                  <span id="moreInfoContainer"></span>
                                  <noscript><ID id="moreInformation">Informations</ID></noscript>
                              </td>
                          </tr>
                      </table>
                    </h4>
                    <div id="infoBlockID" class="infoBlock" style="display: none">
                        <p>
                            <ID id="errorExpl1">Ce problème peut avoir différentes causes, notamment :</ID>
                            <ul>
                                <li id="errorExpl2">La connexion Internet a été perdue.</li>
                                <li id="errorExpl3">Le site Web est temporairement indisponible.</li>
                                <li id="errorExpl4">Le serveur de noms de domaine (DNS) est inaccessible.</li>
                                <li id="errorExpl5">Le serveur de noms de domaine (DNS) ne contient pas d’entrée pour le domaine du site Web.</li>
                                <li id="errorExpl7">Il se peut que l’adresse contienne une erreur de frappe.</li> 
                                <li id="errorExpl6">S’il s’agit d’une adresse HTTPS (sécurisée), cliquez sur Outils, sur Options Internet, puis sur Avancées et vérifiez que les protocoles SSL et TLS sont activés dans la section relative à la sécurité.</li>
                            </ul>
                        </p>
                        <p id="offlineUsers"><b>Pour les utilisateurs hors connexion</b></p>                                     
                        <p id="viewSubscribedFeeds1">
                           Vous pouvez encore afficher les flux auxquels vous êtes abonné et certaines pages Web visitées.

                           Pour afficher les flux auxquels vous êtes abonné
                           <ol>
                               <li id="viewSubscribedFeeds2">Cliquez sur le bouton Centre des favoris <img src="favcenter.png" border="0">, cliquez sur Flux, puis cliquez sur le flux que vous souhaitez afficher.</li>
                           </ol>
                        </p>
                        <p id="viewRecentWebpages1">Pour afficher les dernières pages Web visitées (peut ne pas fonctionner pour toutes les pages)
                           <ol>
                              <li id="viewRecentWebpages2">Cliquez sur Outils <img src="tools.png" border="0">, puis sur Travailler hors connexion.</li>
                              <li id="viewRecentWebpages3">Cliquez sur le bouton Centre des favoris <img src="favcenter.png" border="0">, cliquez sur Historique, puis cliquez sur la page que vous souhaitez afficher.</li>
                           </ol>
                        </p>
                    </div>
                </td>
            </tr>
 
        </table>
 
    </body>
</html>

sry my bad

The HTML code you posted above doesn't look the slightest bit like what you are sending in the code:

 plen=es.ES_fill_tcp_data_p(buf,0,PSTR("HTTP/1.0 200 OK\r\nContent-Type: text/html\r\n\r\n"));
  plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<left>Arduino web server test</LEFT> "));
  plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<body bgcolor=\"#000000\"> "));
  plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<font color=\"#FFFFFF\"><FONT FACE=\"arial\"><RIGHT><I><FONT SIZE=1>BTCAD.<U> V1.0 beta</U></h1></FONT></FONT></I> </RIGHT> "));
  plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("<FONT SIZE=3> <font color=\"#00FF00\"></h1><a href=\"http://192.168.1.1\">192.168.1.1<a></FONT></FONT>"));

Where is "Arduino web server test" for example?

I want you to post the HTML code (the page) that your sketch generates.

Anyway, these lines:

 plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("
<form METHOD=get action=\""));
  plen=es.ES_fill_tcp_data(buf,plen,baseurl);
  plen=es.ES_fill_tcp_data_p(buf,plen,PSTR("\">"));

... are going to generate a "send" to the address in baseurl.

baseurl is:

static char baseurl[]="http://192.168.1.15/";

That address is a private address, not routable, and thus this will certainly fail.

Make a try

http://guillaume.redirectme.net:confused: that it is my router

http://guillaume.redirectme.net:85/ that it is suppose to be my Arduino web server

i will test sometthing

Er, right. Then isn't baseurl supposed to be "http://guillaume.redirectme.net:85/"?

Below is a test page I use with my dynamic ip service for outside connections.

//zoomkat 9-20-11
//form GET code
//for use with IDE 0021
//open serial monitor to see what the arduino receives
//use the \ slash to escape the " in the html 
//address will look like http://zoomkat.no-ip.com:84/ when submited
//put http://zoomkat.no-ip.com:84 in your brouser
//for use with W5100 based ethernet shields

#include <SPI.h>
#include <Ethernet.h>

byte mac[] = { 
  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; //physical mac address
byte ip[] = { 
  192, 168, 1, 102 }; // ip in lan
byte gateway[] = { 
  192, 168, 1, 1 }; // internet access via router
byte subnet[] = { 
  255, 255, 255, 0 }; //subnet mask
Server server(84); //server port

String readString; 

//////////////////////

void setup(){

  pinMode(4, OUTPUT); //pin selected to control
  //start Ethernet
  Ethernet.begin(mac, ip, gateway, subnet);
  server.begin();

  //enable serial data print 
  Serial.begin(9600); 
  Serial.println("servertest1"); // so I can keep track of what is loaded
}

void loop(){
  // Create a client connection
  Client client = server.available();
  if (client) {
    while (client.connected()) {
      if (client.available()) {
        char c = client.read();

        //read char by char HTTP request
        if (readString.length() < 100) {

          //store characters to string 
          readString += c; 
          //Serial.print(c);
        } 

        //if HTTP request has ended
        if (c == '\n') {

          ///////////////
          Serial.println(readString);

          //now output HTML data header

          client.println("HTTP/1.1 200 OK");
          client.println("Content-Type: text/html");
          client.println();

          client.println("<HTML>");
          client.println("<HEAD>");
          client.println("<TITLE>Arduino GET test page</TITLE>");
          client.println("</HEAD>");
          client.println("<BODY>");

          client.println("<H1>HTML form GET example</H1>");

          client.println("<FORM ACTION=\"http://zoomkat.no-ip.com:84\" method=get >");

          client.println("Pin 4 \"on\" or \"off\": <INPUT TYPE=TEXT NAME=\"LED\" VALUE=\"\" SIZE=\"25\" MAXLENGTH=\"50\">
");

          client.println("<INPUT TYPE=SUBMIT NAME=\"submit\" VALUE=\"Change Pin 4!\">");

          client.println("</FORM>");

          client.println("
");

          client.println("</BODY>");
          client.println("</HTML>");

          delay(1);
          //stopping client
          client.stop();

          /////////////////////
          if(readString.indexOf("on") >0)//checks for on
          {
            digitalWrite(4, HIGH);    // set pin 4 high
            Serial.println("Led On");
          }
          if(readString.indexOf("off") >0)//checks for off
          {
            digitalWrite(4, LOW);    // set pin 4 low
            Serial.println("Led Off");
          }
          //clearing string for next read
          readString="";

        }
      }
    }
  }
}

one more chunk of test cod. Note the use of http://zoomkat.no-ip.com:84/ as the internet URL to get the page, and the use of the shortened URL for the buttons (href="/?on") as the button URL is the same server as the page server.

//zoomkat 11-25-11
//simple button GET with iframe code
//for use with IDE 0021
//open serial monitor to see what the arduino receives
//use the \ slash to escape the " in the html 
//address will look like http://192.168.1.102:84/ when submited
//or http://zoomkat.no-ip.com:84/ from the internet
//for use with W5100 based ethernet shields

#include <SPI.h>
#include <Ethernet.h>

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; //physical mac address
byte ip[] = { 192, 168, 1, 102 }; // ip in lan
byte gateway[] = { 192, 168, 1, 1 }; // internet access via router
byte subnet[] = { 255, 255, 255, 0 }; //subnet mask
byte myserver[] = { 208, 104, 2, 86 }; // zoomkat web page
Server server(84); //server port
Client client(myserver, 80);
String readString; 

//////////////////////

void setup(){

  pinMode(4, OUTPUT); //pin selected to control
  Ethernet.begin(mac, ip, gateway, subnet);
  server.begin();
  Serial.begin(9600); 
  Serial.println("server/client test 11/25/11"); // so I can keep track of what is loaded
}

void loop(){
  // check for serial input
  if (Serial.available() > 0) 
  {
    byte inChar;
    inChar = Serial.read();
    if(inChar == 'e')
    {
      sendGET(); // call sendGET function
    }
  }  

  Client client = server.available();
  if (client) {
    while (client.connected()) {
      if (client.available()) {
        char c = client.read();

        //read char by char HTTP request
        if (readString.length() < 100) {

          //store characters to string 
          readString += c; 
          //Serial.print(c);
        } 

        //if HTTP request has ended
        if (c == '\n') {

          ///////////////
          Serial.println(readString); //print to serial monitor for debuging 

            //now output HTML data header
          if(readString.indexOf('?') >=0) { //don't send new page
            client.println("HTTP/1.1 204 Zoomkat");
            client.println();
            client.println();  
          }
          else {
            client.println("HTTP/1.1 200 OK"); //send new page
            client.println("Content-Type: text/html");
            client.println();

            client.println("<HTML>");
            client.println("<HEAD>");
            client.println("<TITLE>Arduino GET test page</TITLE>");
            client.println("</HEAD>");
            client.println("<BODY>");

            client.println("<H1>Zoomkat's simple Arduino button</H1>");

            client.println("<a href=\"/?on\" target=\"inlineframe\">ON</a>"); 
            client.println("<a href=\"/?off\" target=\"inlineframe\">OFF</a>"); 

            //client.println("<IFRAME name=inlineframe src=\"res://D:/WINDOWS/dnserror.htm\" width=1 height=1\">");
            client.println("<IFRAME name=inlineframe style=\"display:none\" >");          
            client.println("</IFRAME>");

            client.println("</BODY>");
            client.println("</HTML>");
          }

          delay(1);
          //stopping client
          client.stop();

          ///////////////////// control arduino pin
          if(readString.indexOf("on") >0)//checks for on
          {
            digitalWrite(4, HIGH);    // set pin 4 high
            Serial.println("Led On");
          }
          if(readString.indexOf("off") >0)//checks for off
          {
            digitalWrite(4, LOW);    // set pin 4 low
            Serial.println("Led Off");
          }
          //clearing string for next read
          readString="";

        }
      }
    }
  }
} 

//////////////////////////
void sendGET() //client function to send/receie GET request data.
{
  if (client.connect()) {
    Serial.println("connected");
    client.println("GET /~shb/arduino.txt HTTP/1.0");
    client.println();
  } 
  else {
    Serial.println("connection failed");
    Serial.println();
  }

  while(client.connected() && !client.available()) delay(1); //waits for data
  while (client.connected() || client.available()) { //connected or data available
    char c = client.read();
    Serial.print(c);
  }

  Serial.println();
  Serial.println("disconnecting.");
  Serial.println("==================");
  Serial.println();
  client.stop();

}

Did you try using simply "/" as baseurl? All references are relative, so it should "just work" at that point.