Regex for IP Address

Question

Hi All, 
 Anybody can please me for regexmatch code IPv6 Ip Address. I an using this regex code "^([0-9a-fA-F]{0,4}:){7}[0-9a-fA-F]{0,4}$" 
 Using above code this scenario: 
 a) :2551:FFFF::3333:4566:3456:0 i s also vaild but I don't want to start IP address with any special character. 
 Some of the example below that I want to match regex code valid and invaild like: 
 a) :2551:FFFF::3333:4566:3456:0 (Invalid) 
 b) 1001:2551:FFFF:255b:1222:3333:4566:3456 (valid) 1001:2551:F:255b:1222:3333:4566:3456 (valid) 
 c) 1001:::255b::::3456 (vaild) 
 d) 1001:::255b:::456: (invalid) 
 I need a regex match code which passed all the above mention examples. 
 
 Thanks

Mike Schmitt · Answer

This will be tricky if you're expecing it to accept all possible combinations including the shortform notation where zero-segments can be skipped with the "::" notation. I assume it's possible but your match pattern will probably end up quite a bit more complicated. 
 A quick google result (leading to StackOverflow ) suggests this pattern might work (i'm not 100% sure how Appian-compatible this will be, but it seems to work for me at a first glance) (?:^|(?<=\s))(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,7}:|([0-9a-fA-F]{1,4}:){1,6}:[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,5}(:[0-9a-fA-F]{1,4}){1,2}|([0-9a-fA-F]{1,4}:){1,4}(:[0-9a-fA-F]{1,4}){1,3}|([0-9a-fA-F]{1,4}:){1,3}(:[0-9a-fA-F]{1,4}){1,4}|([0-9a-fA-F]{1,4}:){1,2}(:[0-9a-fA-F]{1,4}){1,5}|[0-9a-fA-F]{1,4}:((:[0-9a-fA-F]{1,4}){1,6})|:((:[0-9a-fA-F]{1,4}){1,7}|:)|fe80:(:[0-9a-fA-F]{0,4}){0,4}%[0-9a-zA-Z]{1,}|::(ffff(:0{1,4}){0,1}:){0,1}((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\.){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])|([0-9a-fA-F]{1,4}:){1,4}:((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\.){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9]))(?=\s|$)
 
 Edit: i tried it out and it seems to work as-desired for all your examples except "c", though i think your example "c" might actually not be valid without editing (i think maybe only one "::" shortcut is valid in the sequence? not sure.)

Mike Schmitt · Answer

jojog0003 said: According to my scenerio the above IP address is Invaild 
 Can you clarify whether you intend to accept the shortform notation of "::" implying that all in-between segments are just "0"? This is what the standard I looked up said - and this suggests that the quoted example is valid (i don't know much more about it than that). 
 Here's the standard I was referencing earlier: https://www.ibm.com/docs/en/ts4500-tape-library?topic=functionality-ipv4-ipv6-address-formats 
 relevant similar example is the one highlighted: