- SJphone responds to port 5060 no matter what source port/rport/... is set
- SJphone doesn't separate displayname and URI in To
- UAs to fingerprint:

	- Twinkle softphone (done)
	- Grandstream ATA series devices
	- some Linksys ATAs
	- freenet iPhone
	- SJPhone (done)
	- snom 190/320/360


- DrayTek routers cause different results for two calls
	- first INVITE: 100 Trying, 180 Ringing
	- second INVITE: 100 Trying, 486, 486, 486 (retransmissions)

- Siemens SX553 doesn't answer to any packets from us
- Content-Type written all-lowercase on DrayTek routers
- trailing whitespaces in Content-Length: header (DrayTek Routers)
- BYE/CANCEL request triggers 404 on LANCOM PBX
- missing 'sip:' in To/BYE triggers 400 Illegal Header on AVM Fritz!
- monitor Allow-Events (supported on Snom, <add more>)

