Daniel Miller
Daniel Miller
Nmap doesn't do this because it's not a recommended configuration (https://serverfault.com/questions/618700/why-multiple-ptr-records-in-dns-is-not-recommended). Nevertheless, it's possible we may want to show the result, so we'll consider it.
Important updates: * **ALL** connect scans are affected, not only localhost. * I have checked and Nmap 6.40 and Nmap 5.35DC1 are also affected. I believe this is related to...
Ok, this is really weird. When debugging, the outcome depends on where I place the breakpoints relative to the select() call. * If I place the breakpoint just prior to...
Adding a `usleep(1500000)` (1.5 seconds) immediately preceding the `select()` results in correct behavior, but `usleep(1000000)` (1 second) fails.
The timeout is too short. Apparently WinSock is delaying the error notification for RST by up to 1.5 seconds. We'll have to add an artificial delay to compensate. We should...
It's delaying because it's doing 3 retransmissions before giving up. This can be controlled with the `TcpMaxConnectRetransmissions` Registry setting. The `TCP_MAXRT` socket option sets a timeout on this behavior, but...
Unfortunately, setting `TCP_MAXRT` means that we only ever get `WSAETIMEDOUT` error code back, even if a RST was received. This means that we can't distinguish an actual timeout from a...
When I was looking into this last time, I asked on StackOverflow: [Windows sockets: How to immediately detect TCP RST on nonblocking connect()?](https://stackoverflow.com/questions/63676682/windows-sockets-how-to-immediately-detect-tcp-rst-on-nonblocking-connect). No answer as yet, but a useful...
Recent research has yielded all the necessary parts to fix this issue, so I'm dumping them here for later. There are 4 parameters to consider: 1. The overall connect timeout...
For comparison, Linux kernel docs for `tcp_syn_retries` state: > Default value is 6, which corresponds to 63seconds till the last retransmission with the current initial RTO of 1second. With this...