Re: DNSSEC & WIldcards

15 Mar 2024

      Looks like your DNS server correctly queues up the RRs, but erronously
believes it can drop data from the Authority section without setting the
TC bit.

Reducing the bufsize so the answer doesn't fit makes trucation work:

bjorn@miraculix:~$ dig a www.app.linktechs.net. +dnssec +multiline +norecur @139.60.210.20 +bufsize=512
;; Truncated, retrying in TCP mode.

; <<>> DiG 9.18.24-1-Debian <<>> a www.app.linktechs.net. +dnssec +multiline +norecur @139.60.210.20 +bufsize=512
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 5946
;; flags: qr aa; QUERY: 1, ANSWER: 3, AUTHORITY: 3, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags: do; udp: 1280
;; QUESTION SECTION:
;www.app.linktechs.net. IN A

;; ANSWER SECTION:
www.app.linktechs.net.  3600 IN A 139.60.210.81
www.app.linktechs.net.  3600 IN RRSIG A 8 3 3600 (
                                20240427232616 20240313222616 37041 linktechs.net.
                                NYC/4H2VZg12vj+tiWVkEROhXwm7JkBna6RQg6LO8kXr
                                oosDUpGnxrgOtJYsWYbYfM58opiC1OeAbcaCB9+nctIU
                                grrwcpuhmvlXYLZi1n/oAmelPldnQ6Hf93HuHi4ULFsS
                                Qfsoo8sdfjt/YSJ4WxjmsM9LMbZ2CZPMU44a3MdftGW1
                                fNKmZ1fLtVreP41KmvP6b01lyUMvjrvT26Yq57DgUDTo
                                iqU5skT+OHzx6ERJkt3tzzwm2pBMvBWFDXC668NtouIW
                                s3mrhJRBuNW3xSCsroaLQ0vmdml2BqNNh7MZNc38FNMJ
                                eh+ts3mbMnOOkzlI1Q8gKMMCWv+VRmv2DA== )
www.app.linktechs.net.  3600 IN RRSIG A 8 3 3600 (
                                20240427232616 20240313222616 11340 linktechs.net.
                                Th3OcZwOMNUb1zMdipnTnFdgFEaOGJ/VofQOTyxmnNCg
                                wl+1Q7eiQ89KHAWEDBisxd0S+EHu6/YBWY2srNx5q58P
                                XIZJ9oQXCqDLzSE884DTQNDEVrSMoKJ9slRU4N4Lj5tT
                                9LzbODmCM9ytRavOKXJHIddQa0MZT4p9cV8K2HI7XSFX
                                0rjieKFa7wDRJqhKyqrT3Rh/S93pavhKWUgN3GVO6hkI
                                H5F67UFpZK7o7nRlyqvM42ep5XaRZS/WJtLuXcTk/QM3
                                MBPTDWgJ0Bh8qpNuHDOb2XFH2I5dwjeKxuYCzeQzN1hL
                                gsmw3d1J2pNsYbC40jmi1bZr0bz2fDurIA== )

;; AUTHORITY SECTION:
_acme-challenge.app.linktechs.net. 1200 IN NSEC auto.linktechs.net. TXT RRSIG NSEC
_acme-challenge.app.linktechs.net. 1200 IN RRSIG NSEC 8 4 1200 (
                                20240427232616 20240313222616 11340 linktechs.net.
                                grjacRLmt+h5UMJkWMgrxeeY4m8kzNCokMsEFAi/10ld
                                2zcx7IZnB5oljSoZo2ZoqN0DEWVOrORGaU0kAcXDIwmD
                                89JG728W78+gikb8D+rpcSejfpAO8tRFO9saPSDY72uk
                                oP0Wle87oMcKmP9EXGcgsTZhd6Dld9qcAlUByGAZC/bi
                                SL5SDeALjpdqzXPXivP597VyJGakeEEjW0y2SmUOIDcg
                                6lOcSGX1QdmbaiHyAxHSjBsg4VV2Qpo2Br75xyfw3o1Z
                                oHMeacsAhhz5HQhtzv9DzULzmtmoA5sQn2VyBm2kcS+S
                                ZKpKioFnHj9BtOv3dn/F5hrQFhEInNPROw== )
_acme-challenge.app.linktechs.net. 1200 IN RRSIG NSEC 8 4 1200 (
                                20240427232616 20240313222616 37041 linktechs.net.
                                bt6W5P4VDC5fs2r/lxwSnI8bhqS2MH7n67Gd2EK6+DDx
                                HYy9MAmSZEy2OYGg7QHamrWr2I+Bq2Og8A0bRRA5TitQ
                                VcWyq3b+VpXUPukg7bmXl4KRNGxdAB8NysoOT75yvPTe
                                Jy1baNzYv9/in6rf8VKXUrKSPUqcAsK3Sz5QHkuzzaIP
                                d+u5m59DAlobNi17QbRGKIQaXTtgkSHpj4rt61MMEzpB
                                JDXE5FRLCJ4pqQPm+DcF0ZrKoYqKv/1rYZSVbW3rY0XB
                                VEBDVy5MJg0YenhbVPcDM9OYh2dfvh5ZvYS6xsXZulv8
                                mKnjdJo7v6qAzPNvIhymghM+0Tp8INxAjw== )

;; Query time: 120 msec
;; SERVER: 139.60.210.20#53(139.60.210.20) (TCP)
;; WHEN: Fri Mar 15 18:57:20 CET 2024
;; MSG SIZE  rcvd: 1326

And directly using tcp also works:

bjorn@miraculix:~$ dig a www.app.linktechs.net. +dnssec +multiline +norecur @139.60.210.20 +vc

; <<>> DiG 9.18.24-1-Debian <<>> a www.app.linktechs.net. +dnssec +multiline +norecur @139.60.210.20 +vc
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 29513
;; flags: qr aa; QUERY: 1, ANSWER: 3, AUTHORITY: 3, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags: do; udp: 1280
;; QUESTION SECTION:
;www.app.linktechs.net. IN A

;; ANSWER SECTION:
www.app.linktechs.net.  3600 IN A 139.60.210.81
www.app.linktechs.net.  3600 IN RRSIG A 8 3 3600 (
                                20240427232616 20240313222616 37041 linktechs.net.
                                NYC/4H2VZg12vj+tiWVkEROhXwm7JkBna6RQg6LO8kXr
                                oosDUpGnxrgOtJYsWYbYfM58opiC1OeAbcaCB9+nctIU
                                grrwcpuhmvlXYLZi1n/oAmelPldnQ6Hf93HuHi4ULFsS
                                Qfsoo8sdfjt/YSJ4WxjmsM9LMbZ2CZPMU44a3MdftGW1
                                fNKmZ1fLtVreP41KmvP6b01lyUMvjrvT26Yq57DgUDTo
                                iqU5skT+OHzx6ERJkt3tzzwm2pBMvBWFDXC668NtouIW
                                s3mrhJRBuNW3xSCsroaLQ0vmdml2BqNNh7MZNc38FNMJ
                                eh+ts3mbMnOOkzlI1Q8gKMMCWv+VRmv2DA== )
www.app.linktechs.net.  3600 IN RRSIG A 8 3 3600 (
                                20240427232616 20240313222616 11340 linktechs.net.
                                Th3OcZwOMNUb1zMdipnTnFdgFEaOGJ/VofQOTyxmnNCg
                                wl+1Q7eiQ89KHAWEDBisxd0S+EHu6/YBWY2srNx5q58P
                                XIZJ9oQXCqDLzSE884DTQNDEVrSMoKJ9slRU4N4Lj5tT
                                9LzbODmCM9ytRavOKXJHIddQa0MZT4p9cV8K2HI7XSFX
                                0rjieKFa7wDRJqhKyqrT3Rh/S93pavhKWUgN3GVO6hkI
                                H5F67UFpZK7o7nRlyqvM42ep5XaRZS/WJtLuXcTk/QM3
                                MBPTDWgJ0Bh8qpNuHDOb2XFH2I5dwjeKxuYCzeQzN1hL
                                gsmw3d1J2pNsYbC40jmi1bZr0bz2fDurIA== )

;; AUTHORITY SECTION:
_acme-challenge.app.linktechs.net. 1200 IN NSEC auto.linktechs.net. TXT RRSIG NSEC
_acme-challenge.app.linktechs.net. 1200 IN RRSIG NSEC 8 4 1200 (
                                20240427232616 20240313222616 11340 linktechs.net.
                                grjacRLmt+h5UMJkWMgrxeeY4m8kzNCokMsEFAi/10ld
                                2zcx7IZnB5oljSoZo2ZoqN0DEWVOrORGaU0kAcXDIwmD
                                89JG728W78+gikb8D+rpcSejfpAO8tRFO9saPSDY72uk
                                oP0Wle87oMcKmP9EXGcgsTZhd6Dld9qcAlUByGAZC/bi
                                SL5SDeALjpdqzXPXivP597VyJGakeEEjW0y2SmUOIDcg
                                6lOcSGX1QdmbaiHyAxHSjBsg4VV2Qpo2Br75xyfw3o1Z
                                oHMeacsAhhz5HQhtzv9DzULzmtmoA5sQn2VyBm2kcS+S
                                ZKpKioFnHj9BtOv3dn/F5hrQFhEInNPROw== )
_acme-challenge.app.linktechs.net. 1200 IN RRSIG NSEC 8 4 1200 (
                                20240427232616 20240313222616 37041 linktechs.net.
                                bt6W5P4VDC5fs2r/lxwSnI8bhqS2MH7n67Gd2EK6+DDx
                                HYy9MAmSZEy2OYGg7QHamrWr2I+Bq2Og8A0bRRA5TitQ
                                VcWyq3b+VpXUPukg7bmXl4KRNGxdAB8NysoOT75yvPTe
                                Jy1baNzYv9/in6rf8VKXUrKSPUqcAsK3Sz5QHkuzzaIP
                                d+u5m59DAlobNi17QbRGKIQaXTtgkSHpj4rt61MMEzpB
                                JDXE5FRLCJ4pqQPm+DcF0ZrKoYqKv/1rYZSVbW3rY0XB
                                VEBDVy5MJg0YenhbVPcDM9OYh2dfvh5ZvYS6xsXZulv8
                                mKnjdJo7v6qAzPNvIhymghM+0Tp8INxAjw== )

;; Query time: 120 msec
;; SERVER: 139.60.210.20#53(139.60.210.20) (TCP)
;; WHEN: Fri Mar 15 18:57:56 CET 2024
;; MSG SIZE  rcvd: 1326

So you might be able to configure yourself oout of that by simply
dropping one of the ZSKs, reducing the number of signatures.  And/or
using an algorithm with shorter signatures.

But it will always be fragile.

Bjørn

Re: DNSSEC & WIldcards

Bjørn Mork