Nmap Development mailing list archives
Re: nmap: [REGRESSION 5.00-3 -> 6.00-0.3] -sP fails with "nexthost: failed to determine route to X.X.X.X"
From: Timo Juhani Lindfors <timo.lindfors () iki fi>
Date: Tue, 06 Aug 2013 10:30:26 +0300
David Fifield <david () bamsoftware com> writes:
I haven't been able to reproduce it yet, but I haven't been on a (simulated) network with more than 1024 live hosts.
I did not have 1024 hosts in my network either. Even an empty network was enough to reproduce the issue here.
the proximate cause of the the problem you encountered. A good quick test is to edit libnetutil/netutil.cc to disable route_dst_netlink and enable route_dst_generic, and see if the problem persists.
That doesn't seem to help.
Another thing to try: The --route-dst option makes Nmap make a routing decision, without sending pings or any other traffic. Try something like sudo nmap --route-dst 10.7.24.1 and see if it increases the number of ARP entries in the cache. If so, we will have the problem localized closely.
It does: $ for i in $(seq 20 30); do sudo nmap --route-dst 10.7.24.$i > /dev/null 2>&1; ip ntable show dev eth0 name arp_cache | grep refcnt; done refcnt 17 reachable 26920 base_reachable 30000 retrans 1000 refcnt 18 reachable 26920 base_reachable 30000 retrans 1000 refcnt 19 reachable 26920 base_reachable 30000 retrans 1000 refcnt 20 reachable 26920 base_reachable 30000 retrans 1000 refcnt 21 reachable 26920 base_reachable 30000 retrans 1000 refcnt 22 reachable 26920 base_reachable 30000 retrans 1000 refcnt 23 reachable 26920 base_reachable 30000 retrans 1000 refcnt 24 reachable 26920 base_reachable 30000 retrans 1000 refcnt 25 reachable 26920 base_reachable 30000 retrans 1000 refcnt 26 reachable 26920 base_reachable 30000 retrans 1000 refcnt 27 reachable 26920 base_reachable 30000 retrans 1000 _______________________________________________ Sent through the dev mailing list http://nmap.org/mailman/listinfo/dev Archived at http://seclists.org/nmap-dev/
Current thread:
- nmap: [REGRESSION 5.00-3 -> 6.00-0.3] -sP fails with "nexthost: failed to determine route to X.X.X.X" Timo Juhani Lindfors (Jul 05)
- Re: nmap: [REGRESSION 5.00-3 -> 6.00-0.3] -sP fails with "nexthost: failed to determine route to X.X.X.X" David Fifield (Jul 31)
- Re: nmap: [REGRESSION 5.00-3 -> 6.00-0.3] -sP fails with "nexthost: failed to determine route to X.X.X.X" Daniel Miller (Jul 31)
- Re: nmap: [REGRESSION 5.00-3 -> 6.00-0.3] -sP fails with "nexthost: failed to determine route to X.X.X.X" David Fifield (Jul 31)
- Re: nmap: [REGRESSION 5.00-3 -> 6.00-0.3] -sP fails with "nexthost: failed to determine route to X.X.X.X" Timo Juhani Lindfors (Aug 06)
- Re: nmap: [REGRESSION 5.00-3 -> 6.00-0.3] -sP fails with "nexthost: failed to determine route to X.X.X.X" Daniel Miller (Jul 31)
- Re: nmap: [REGRESSION 5.00-3 -> 6.00-0.3] -sP fails with "nexthost: failed to determine route to X.X.X.X" Timo Juhani Lindfors (Aug 06)
- Re: nmap: [REGRESSION 5.00-3 -> 6.00-0.3] -sP fails with "nexthost: failed to determine route to X.X.X.X" David Fifield (Jul 31)