NS

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... SRV RR adds 20 bytes plus the name of the target host; each NS RR in the NS ...

... target host; each NS RR in the NS section is 15 bytes plus the name of the name server host ...

... RR in the additional data section is 20 bytes or so, and there are A's for each SRV and NS RR mentioned in the answer. This size estimate is extremely crude, but shouldn't underestimate ...

... TTL than the SRV or NS RR's.) ...

... root.asdf.com. ( 1995032001 3600 3600 604800 86400 ) NS server.asdf.com. NS ns1.ip-provider ...

... NS server.asdf.com. NS ns1.ip-provider.net. NS ...

... NS ns1.ip-provider.net. NS ns2.ip-provider.net. ftp.tcp SRV ...

... query section is quoted here and doesn't need to be counted again. 75 bytes for 3 NS RRs, 15 bytes each plus the lengths of "server", "ns1.ip-provider ...

... 120 bytes for the 6 A RR's mentioned by the SRV and NS RR's. ...