Forward and reverse DNS for Card validator crawler do not match


#1

According to docs there are multiple IPs of crawler:

199.59.148.209
199.59.148.210
199.59.148.211
199.16.156.124
199.16.156.125
199.16.156.126

first 3 of these have reverse DNS records:

In [18]: socket.gethostbyaddr('199.59.148.209')                                                               
Out[18]: ('r-199-59-148-209.twttr.com', [], ['199.59.148.209'])

In [19]: socket.gethostbyaddr('199.59.148.210')                                                               
Out[19]: ('r-199-59-148-210.twttr.com', [], ['199.59.148.210'])

In [20]: socket.gethostbyaddr('199.59.148.211')                                                               
Out[20]: ('r-199-59-148-211.twttr.com', [], ['199.59.148.211'])

But forward lookups for these domain return different IP address:

In [21]: socket.gethostbyname('r-199-59-148-209.twttr.com')                                                   
Out[21]: '23.21.224.150'

In [22]: socket.gethostbyname('r-199-59-148-210.twttr.com')                                                   
Out[22]: '23.21.224.150'

In [23]: socket.gethostbyname('r-199-59-148-211.twttr.com')                                                   
Out[23]: '23.21.224.150'

It’s not critical because all IP addresses of crawler are listed in docs but it’s common practice to validate bots by forward and reverse DNS lookups:

In [25]: socket.gethostbyaddr('157.55.33.18')                                                              
Out[25]: ('msnbot-157-55-33-18.search.msn.com', [], ['157.55.33.18'])

In [26]: socket.gethostbyname('msnbot-157-55-33-18.search.msn.com')
Out[26]: '157.55.33.18'

In [27]: socket.gethostbyaddr('66.249.66.1')                                                                  
Out[27]: ('crawl-66-249-66-1.googlebot.com', [], ['66.249.66.1'])

In [28]: socket.gethostbyname('crawl-66-249-66-1.googlebot.com')                                      
Out[28]: '66.249.66.1'

Is it possible to fix forward and reverse lookups of twitterbot crawler?