[SIPForum-discussion] rfc-conform contact-header

[Paul Kyzivat]

On 2/11/16 11:00 AM, Guenter, Uli (Uli) wrote:
> Hello,
>
> I would like to know your thoughts if this contact header is rfc-conform or not:
>
> Contact: <sip:wsg1TLz4Zbiqx7a2mhQNOjxYO2B1KqLAjaPkzVN7mUnDRqMkzvk4H3Bcvg/YWyDZ at th1>


It appears to by *syntactically* valid.

But the hostname has only "th1" as a TLD. AFAIK this is not a valid TLD. 
Also, AFAIK there are no TLDs that are themselves resolvable. There 
would normally have to be at least one sub domain of the TLD before 
having something resolvable.

I guess it might be resolvable if it was resolved by a host that had had 
a default domain that this would be resolved relative to. But then it 
would only be usable in environments where all users resolved it that 
way. While I guess that isn't *forbidden*, it is certainly bad practice.

	Thanks,
	Paul