I have ServerA (running Ubuntu 12.04 (IP:, a KVM DomU of an also Ubuntu Dom0 that is trying to perform a scan against ServerB-ServerZ (Mixed OS (IPs: using the command: nmap -vv --stats-every 5s -sS -R -p 1-65535

Now everytime I do this all my connections get blocked on the machine performing the scan (incoming and outgoing). This with iptables and ufw disabled, rules flushed etc... I can ping the gateway perfectly before the scan start and during most of the scan until a point where I lose all connectivity... At that point I can still access the machine via console and there is no high loads etc...

Something is wrong with the syn scan... I attempted doing a FIN scan that worked.

Also I monitored most of the logs using the command tail -f /var/logs/*.log but also didn't get anything suspicious

Any pointers would be appreciated.

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Browse other questions tagged or ask your own question.