Nmap Development mailing list archives
ACK is being sent with a sequence of 0 every time.
From: James Rogers <jamesmrogers () gmail com>
Date: Wed, 13 Jun 2012 15:35:50 -0400
As I was working on the spurious port closed bug I noticed something strange: we don't set a sequence number in the ACK packets we send. SENT (0.5123s) TCP 10.0.1.103:46853 > 74.207.254.18:80 A ttl=44 id=49043 iplen=40 >>>>> seq=0 <<<< win=1024 as you can see the seq=0. According to what I think I am reading ACK packets are supposed to have a sequence number set too. It is a big red flag to always be sending the same seq number in the same kind of packet. In "scan_engine.cc" [Modified] line 3372 of 6239 if (pspec->pd.tcp.flags & TH_ACK) ack = seq32_encode(USI, tryno, pingseq); else seq = seq32_encode(USI, tryno, pingseq); So the ack packet will not set a sequence number. When I tried this: if (pspec->pd.tcp.flags & TH_ACK) ack = seq32_encode(USI, tryno, pingseq); seq = seq32_encode(USI, tryno, pingseq); it worked in adding a seq to the ACK segment, but the send to 443 and to 80 then had the same seq number, which would just be confusing. Would like input on how to proceed here. Of if this is even a bug. _______________________________________________ Sent through the nmap-dev mailing list http://cgi.insecure.org/mailman/listinfo/nmap-dev Archived at http://seclists.org/nmap-dev/
Current thread:
- ACK is being sent with a sequence of 0 every time. James Rogers (Jun 13)
- Re: ACK is being sent with a sequence of 0 every time. David Fifield (Jun 13)
- Re: ACK is being sent with a sequence of 0 every time. David Fifield (Jun 13)
- Re: ACK is being sent with a sequence of 0 every time. James Rogers (Jun 13)
- Re: ACK is being sent with a sequence of 0 every time. David Fifield (Jun 13)
- Re: ACK is being sent with a sequence of 0 every time. James Rogers (Jun 13)
- Re: ACK is being sent with a sequence of 0 every time. James Rogers (Jun 25)
- Re: ACK is being sent with a sequence of 0 every time. David Fifield (Jun 25)
- Re: ACK is being sent with a sequence of 0 every time. David Fifield (Jun 13)