How to mess up dns round robin and mx records
have 6 different mx records all same priority point at 6 A records that all point to the same 6 servers.
eh?
I wouldn't be surprised if email is looping about then getting bucketed after 5 days. where are the 4 hour warning going.
-bash-3.00$ dig tiscali.co.uk mx
; <<>> DiG 9.2.4 <<>> tiscali.co.uk mx
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 54549
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 2, ADDITIONAL: 2
;; QUESTION SECTION:
;tiscali.co.uk. IN MX
;; ANSWER SECTION:
tiscali.co.uk. 900 IN MX 10 mx5.uk.tiscali.com.
tiscali.co.uk. 900 IN MX 10 mx6.uk.tiscali.com.
tiscali.co.uk. 900 IN MX 10 mx1.uk.tiscali.com.
tiscali.co.uk. 900 IN MX 10 mx2.uk.tiscali.com.
tiscali.co.uk. 900 IN MX 10 mx3.uk.tiscali.com.
tiscali.co.uk. 900 IN MX 10 mx4.uk.tiscali.com.
;; AUTHORITY SECTION:
tiscali.co.uk. 338 IN NS ns0.as9105.com.
tiscali.co.uk. 338 IN NS ns0.tiscali.co.uk.
;; ADDITIONAL SECTION:
ns0.as9105.com. 167206 IN A 212.139.129.130
ns0.tiscali.co.uk. 597739 IN A 212.74.114.132
;; Query time: 16 msec
;; SERVER: 212.20.226.194#53(212.20.226.194)
;; WHEN: Wed May 30 15:23:00 2007
;; MSG SIZE rcvd: 240
-bash-3.00$ host mx5.uk.tiscali.com
mx5.uk.tiscali.com has address 212.74.100.148
mx5.uk.tiscali.com has address 212.74.100.149
mx5.uk.tiscali.com has address 212.74.100.150
mx5.uk.tiscali.com has address 212.74.100.151
mx5.uk.tiscali.com has address 212.74.100.152
mx5.uk.tiscali.com has address 212.74.100.147
-bash-3.00$ host mx6.uk.tiscali.com
mx6.uk.tiscali.com has address 212.74.100.151
mx6.uk.tiscali.com has address 212.74.100.152
mx6.uk.tiscali.com has address 212.74.100.147
mx6.uk.tiscali.com has address 212.74.100.148
mx6.uk.tiscali.com has address 212.74.100.149
mx6.uk.tiscali.com has address 212.74.100.150
-bash-3.00$ host mx4.uk.tiscali.com
mx4.uk.tiscali.com has address 212.74.100.152
mx4.uk.tiscali.com has address 212.74.100.147
mx4.uk.tiscali.com has address 212.74.100.148
mx4.uk.tiscali.com has address 212.74.100.149
mx4.uk.tiscali.com has address 212.74.100.150
mx4.uk.tiscali.com has address 212.74.100.151
-bash-3.00$ host mx3.uk.tiscali.com
mx3.uk.tiscali.com has address 212.74.100.147
mx3.uk.tiscali.com has address 212.74.100.148
mx3.uk.tiscali.com has address 212.74.100.149
mx3.uk.tiscali.com has address 212.74.100.150
mx3.uk.tiscali.com has address 212.74.100.151
mx3.uk.tiscali.com has address 212.74.100.152
-bash-3.00$ host mx2.uk.tiscali.com
mx2.uk.tiscali.com has address 212.74.100.148
mx2.uk.tiscali.com has address 212.74.100.149
mx2.uk.tiscali.com has address 212.74.100.150
mx2.uk.tiscali.com has address 212.74.100.151
mx2.uk.tiscali.com has address 212.74.100.152
mx2.uk.tiscali.com has address 212.74.100.147
-bash-3.00$ host mx1.uk.tiscali.com
mx1.uk.tiscali.com has address 212.74.100.152
mx1.uk.tiscali.com has address 212.74.100.147
mx1.uk.tiscali.com has address 212.74.100.148
mx1.uk.tiscali.com has address 212.74.100.149
mx1.uk.tiscali.com has address 212.74.100.150
mx1.uk.tiscali.com has address 212.74.100.151
-bash-3.00$
and if you do a lookup on dns stuff you will see that none are listed.
This assumes incoming email and outgoign email go through the same server.