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aelius

Administrare servere linux si servicii conexe

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Administrez servere linux (orice distributie) cat si FreeBSD.

 

Experienta in domeniu: 20 de ani

 

In mare, din cunostintele ce le am:

- Politici de securitate atat pe FreeBSD cat si pe linux

- Solutii antispam si solutii de securitate pentru servere de email

- Orice arhitectura de server(e) web (content delivery & caching, dual strat, clusters)

- MySQL, PostgreSQL, PHP

- Tehnici avansate de mitigare atacuri DDoS.

- Sisteme de detectie si prevenire a intruziunilor

 

Instalez, configurez si optimizez orice fel de daemon sau aplicatie open source. De asemenea, ofer consultanta pentru necesitati hardware.

 

Pentru cotatii de pret, trimite un email te rog la  tex at unixteacher dot org (sau un mesaj privat)

 

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      1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 '''     Raw sockets on Linux           Silver Moon (m00n.silv3r@gmail.com) '''   # some imports import socket, sys from struct import *   # checksum functions needed for calculation checksum def checksum(msg):     s = 0           # loop taking 2 characters at a time     for i in range(0, len(msg), 2):         w = ord(msg) + (ord(msg[i+1]) << 8 )         s = s + w           s = (s>>16) + (s & 0xffff);     s = s + (s >> 16);           #complement and mask to 4 byte short     s = ~s & 0xffff           return s   #create a raw socket try:     s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_RAW) except socket.error , msg:     print 'Socket could not be created. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]     sys.exit()   # tell kernel not to put in headers, since we are providing it, when using IPPROTO_RAW this is not necessary # s.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)       # now start constructing the packet packet = '';   source_ip = '192.168.1.101' dest_ip = '192.168.1.1' # or socket.gethostbyname('www.google.com')   # ip header fields ip_ihl = 5 ip_ver = 4 ip_tos = 0 ip_tot_len = 0  # kernel will fill the correct total length ip_id = 54321   #Id of this packet ip_frag_off = 0 ip_ttl = 255 ip_proto = socket.IPPROTO_TCP ip_check = 0    # kernel will fill the correct checksum ip_saddr = socket.inet_aton ( source_ip )   #Spoof the source ip address if you want to ip_daddr = socket.inet_aton ( dest_ip )   ip_ihl_ver = (ip_ver << 4) + ip_ihl   # the ! in the pack format string means network order ip_header = pack('!BBHHHBBH4s4s' , ip_ihl_ver, ip_tos, ip_tot_len, ip_id, ip_frag_off, ip_ttl, ip_proto, ip_check, ip_saddr, ip_daddr)   # tcp header fields tcp_source = 1234   # source port tcp_dest = 80   # destination port tcp_seq = 454 tcp_ack_seq = 0 tcp_doff = 5    #4 bit field, size of tcp header, 5 * 4 = 20 bytes #tcp flags tcp_fin = 0 tcp_syn = 1 tcp_rst = 0 tcp_psh = 0 tcp_ack = 0 tcp_urg = 0 tcp_window = socket.htons (5840)    #   maximum allowed window size tcp_check = 0 tcp_urg_ptr = 0   tcp_offset_res = (tcp_doff << 4) + 0 tcp_flags = tcp_fin + (tcp_syn << 1) + (tcp_rst << 2) + (tcp_psh <<3) + (tcp_ack << 4) + (tcp_urg << 5)   # the ! in the pack format string means network order tcp_header = pack('!HHLLBBHHH' , tcp_source, tcp_dest, tcp_seq, tcp_ack_seq, tcp_offset_res, tcp_flags,  tcp_window, tcp_check, tcp_urg_ptr)   user_data = 'Hello, how are you'   # pseudo header fields source_address = socket.inet_aton( source_ip ) dest_address = socket.inet_aton(dest_ip) placeholder = 0 protocol = socket.IPPROTO_TCP tcp_length = len(tcp_header) + len(user_data)   psh = pack('!4s4sBBH' , source_address , dest_address , placeholder , protocol , tcp_length); psh = psh + tcp_header + user_data;   tcp_check = checksum(psh) #print tcp_checksum   # make the tcp header again and fill the correct checksum - remember checksum is NOT in network byte order tcp_header = pack('!HHLLBBH' , tcp_source, tcp_dest, tcp_seq, tcp_ack_seq, tcp_offset_res, tcp_flags,  tcp_window) + pack('H' , tcp_check) + pack('!H' , tcp_urg_ptr)   # final full packet - syn packets dont have any data packet = ip_header + tcp_header + user_data   #Send the packet finally - the port specified has no effect s.sendto(packet, (dest_ip , 0 ))    # put this in a loop if you want to flood the target Run the above program from the terminal and check the network traffic using a packet sniffer like wireshark. It should show the packet.
      Raw sockets find application in the field of network security. The above example can be used to code a tcp syn flood program. Syn flood programs are used in Dos attacks. Raw sockets are also used to code packet sniffers, port scanners etc.
       
      sursa: Please login or register to see this link.
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