⟩ What are the default ports used for SMTP,DNS,FTP,DHCP,SSH and squid?
Service: Port
SMTP: 25
SSH: 22
Squid: 3128
DNS: 53
FTP: 20 (data transfer) , 21 ( Connection established)
DHCP: 67/UDP(dhcp server) , 68/UDP(dhcp client)
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More Questions for you:
What is the problem with this server program?
#include<stdio.h>
#include<stdlib.h>
#include<netinet/in.h>
#include<sys/types.h>
#include<sys/socket.h>
int main()
{
int fd_server, fd_client, len;
struct sockaddr_in add_server;
fd_server = socket(AF_INET,SOCK_STREAM,0);
if (fd_server == -1){
perror("fd_sock");
exit(1);
}
add_server.sin_family = AF_INET;
add_server.sin_port = htons(4001);
add_server.sin_addr.s_addr = inet_addr("122.23.1.1");
len = sizeof(add_server);
if( bind(fd_server,(struct sockaddr*)&add_server,len) != 0)
perror("bind");
if(listen(fd_server,5) != 0)
perror("listen");
fd_client = accept(fd_server,(struct sockaddr*)&add_server,&len);
if(fd_client == -1)
perror("accept");
return 0;
}
a) it can not accept the request of any client
b) it will give the segmentation fault
c) there is no problem with this program
d) none of the mentWhat is the output of this program no 10?
#include<stdio.h>
#include<stdlib.h>
#include<netinet/in.h>
#include<sys/types.h>
#include<sys/socket.h>
int main()
{
int fd_server, fd_client, len, len_client;
struct sockaddr_in add_server;
fd_server = socket(AF_INET,SOCK_STREAM,0);
fd_client = accept(fd_server,(struct sockaddr*)&add_server,&len);
if(fd_client == -1)
perror("accept");
if(listen(fd_server,5) != 0)
perror("listen");
return 0;
}
a) syntax error
b) error at the time of compilation
c) segmentation fault
d) none of the mentionedWhat is the output of this program no 11?
#include<stdio.h>
#include<stdlib.h>
#include<netinet/in.h>
#include<sys/types.h>
#include<sys/socket.h>
int main()
{
int fd_server, fd_client, len, len_client;
struct sockaddr_in add_server;
fd_server = socket(AF_INET,SOCK_STREAM,0);
close(fd_server);
perror("accept");
if(listen(fd_server,5) != 0)
perror("listen");
fd_client = accept(fd_server,(struct sockaddr*)&add_server,&len);
if(fd_client == -1)
return 0;
}
a) syntax error
b) error at the time of compilation
c) segmentation fault
d) none of the mentionedOn which system call, this program (process) waits until the server responds?
#include<stdio.h>
#include<netinet/in.h>
#include<sys/types.h>
#include<sys/socket.h>
int main()
{
int fd_client,fd, len;
struct sockaddr_in add_server;
fd_client = socket(AF_INET,SOCK_STREAM,0);
if (fd_client == -1){
perror("fd_sock");
exit(1);
}
add_server.sin_family = AF_INET;
add_server.sin_port = ntohs(4001);
add_server.sin_addr.s_addr = inet_addr("127.0.0.1");
len = sizeof(add_server);
fd = connect(fd_client,(struct sockaddr*)&add_server,len);
if(fd == -1)
perror("connect");
write(fd,"Hellon",6);
return 0;
}
a) socket()
b) connect()
c) both (a) and (b)
d) none of the mentionedWhat is the the response of this server for this client if both programs are running on the same system?
/*This is server.c*/
#include<stdio.h>
#include<stdlib.h>
#include<netinet/in.h>
#include<sys/types.h>
#include<sys/socket.h>
int main()
{
int fd_server, fd_client, len, len_client;
struct sockaddr_in add_server, add_client;
char buff[10];
fd_server = socket(AF_INET,SOCK_STREAM,0);
if (fd_server == -1){
perror("fd_sock");
exit(1);
}
add_server.sin_family = AF_INET;
add_server.sin_port = htons(4001);
add_server.sin_addr.s_addr = inet_addr("127.0.0.1");
len = sizeof(add_server);
len = sizeof(add_client);
if( bind(fd_server,(struct sockaddr*)&add_server,len) != 0)
perror("bind");
if(listen(fd_server,5) != 0)
perror("listen");
fd_client = accept(fd_server,(struct sockaddr*)&add_client,&len_client);
if(fd_client == -1)
perror("accept");
read(fd_clWhat is the output of this program no 12?
#include<stdio.h>
int main()
{
int fd_socket;
fd_socket = socket(AF_UNIX,SOCK_STREAM,0);
printf("%dn",fd_socket);
return 0;
}
a) -1
b) 0
c) any integer value
d) none of the mentionedIn this program, the third argument of the socket() is used for _____ potocol.
#include<stdio.h>
#include<sys/types.h>
#include<sys/socket.h>
int main()
{
int fd_socket;
if(socket(AF_UNIX,SOCK_STREAM,0) == -1)
perror("socket");
return 0;
}
a) TCP/IP
b) UDP
c) both (a) and (b)
d) none of mentionedBy this program the soket "san_sock" will create
#include<stdio.h>
#include<sys/types.h>
#include<sys/un.h>
#include<sys/socket.h>
int main()
{
struct sockaddr_un add_server;
int fd_server;
fd_server = socket(AF_UNIX,SOCK_STREAM,0);
if(fd_server == -1)
perror("socket");
add_server.sun_family = AF_UNIX;
strcpy(add_server.sun_path,"san_sock");
if( bind(fd_server,(struct sockaddr*)&add_server,sizeof(add_server)) != 0)
perror("bind");
return 0;
}
a) in the /tmp directory
b) in the /usr directory
c) in the present working directory
d) none of the mentionedWhat is the length of of the queue for pending connections in this program?
#include<stdio.h>
#include<sys/types.h>
#include<sys/un.h>
#include<sys/socket.h>
int main()
{
struct sockaddr_un add_server;
int fd_server;
fd_server = socket(AF_UNIX,SOCK_STREAM,0);
if(fd_server == -1)
perror("socket");
add_server.sun_family = AF_UNIX;
strcpy(add_server.sun_path,"server_sock2");
if( bind(fd_server,(struct sockaddr*)&add_server,sizeof(add_server)) != 0)
perror("bind");
if( listen(fd_server,3) != 0)
perror("listen");
return 0;
}
a) 0
b) 1
c) 2
d) 3What is the output of the program no 13?
#include<stdio.h>
#include<sys/types.h>
#include<sys/un.h>
#include<sys/socket.h>
int main()
{
struct sockaddr_un add_server, add_client;
int fd_server, fd_client;
int len;
char ch;
fd_server = socket(AF_UNIX,SOCK_STREAM,0);
if(fd_server == -1)
perror("socket");
add_server.sun_family = AF_UNIX;
strcpy(add_server.sun_path,"san_sock");
if( bind(fd_server,(struct sockaddr*)&add_server,sizeof(add_server)) != 0)
perror("bind");
if( listen(fd_server,3) != 0)
perror("listen");
len = sizeof(add_client);
fd_client = accept(fd_server,(struct sockaddr*)&add_client,&len);
printf("googlen");
return 0;
}
a) the program will print the string "google"
b) the process will remain block
c) segmentation fault
d) none of the mentioned
