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plurals

PORetrieve ack after syn
primarykey
Id
9262467
data
AcceptedAnswerId
0
AnswerCount
2
ClosedDate
CommentCount
1
CommunityOwnedDate
CreationDate
2012-02-13T14:48:46.597
FavoriteCount
2
LastActivityDate
2013-02-26T07:53:14.800
LastEditDate
2012-02-13T15:43:12.210
LastEditorUserId
298479
OwnerUserId
507033
ParentId
0
PostTypeId
1
Score
2
ViewCount
501
LastEditorDisplayName
text
Body
I've coded a small tool which just throws a syn packet at any ip and port number you give it -- and when I popped up Wireshark, the sent packet appears fine, no errors or anything, it looks just like your typical TCP SYN packet. For some reason, the ACK isn't sent by the server. So, there's two problems; one, no ACK response. Two, I don't even know how to receive the ack response via my program (bind()?). I modified some code from a syn flooder I found online because it seemed like to me some script-kiddie code would be easy to follow, but I'm afraid it may be missing something, and may be the result of the server's ACK denial. The code has been modified so the syn request is sent from the legitimate IP address. The following code shows my ip+tcp headers: <pre><code> iph->ihl = 5; iph->version = 4; iph->tos = 0; iph->tot_len = sizeof (struct ip) + sizeof (struct tcphdr); iph->id = htonl (54321); //Id of this packet iph->frag_off = 0; iph->ttl = 255; iph->protocol = 6; iph->check = 0; //Set to 0 before calculating checksum iph->saddr = 0; //Source ip filled in by kernel iph->daddr = sin.sin_addr.s_addr; //TCP Header tcph->source = htons (9999); tcph->dest = htons (atoi(argv[2])); tcph->seq = random (); // tcph->ack_seq = 0; tcph->doff = 5; /* first and only tcp segment */ tcph->syn = 1; tcph->window = htonl (65555); /* maximum allowed window size */ tcph->check = 0;/* if you set a checksum to zero, your kernel's IP stack should fill in the correct checksum during transmission */ tcph->urg_ptr = 0; //Now the IP checksum iph->check = csum ((unsigned short *) datagram, iph->tot_len >> 1); </code></pre> So, I send that, no ack back. What am I missing?
Tags
<c><linux><raw-sockets>
Title
Retrieve ack after syn
singulars
PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. This table or related slice is empty.
PostTypePostTypeId
1. PTQuestion
UserLastEditorUserId
1. USThiefMaster
UserOwnerUserId
1. USSaustin
plurals
PostLinksPostIdRelatedPostId
1. This table or related slice is empty.
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. This table or related slice is empty.
PostsParentIdCreationDate
1. PO
 singulars
 PostTypePostTypeId
 PTAnswer
2. PO
 singulars
 PostTypePostTypeId
 PTAnswer
VotesPostIdCreationDate
1. VO
 singulars
 PostPostId
 PORetrieve ack after syn
 UserUserId
 USPeter Krejci
 VoteTypeVoteTypeId
 VTFavorite
2. VO
 singulars
 PostPostId
 PORetrieve ack after syn
 UserUserId
 USFatalError
 VoteTypeVoteTypeId
 VTFavorite
3. VO
 singulars
 PostPostId
 PORetrieve ack after syn
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTUpMod
CommentsPostId
1. COLooks like your packet is being discarded. I'd suggest checking with a sniffer at both endpoints.
 singulars
 PostPostId
 PORetrieve ack after syn
 UserUserId
 USjweyrich

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