Web tools
help to find what you need
DNS
www.intodns.com
www.dns-info.cz
DNS DIG
A DNS visualization tool
Whois CZnic
IPv6
6to4 address calculator
IPv6 test page [zotto.cz]
IPv6 test
Cisco
www.zotto.cz - Cisco pass recovery
Other
Ethernet Vendor Code Lookup Tool
Mail server - Test SPF, DomainKeys a DKIM