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Chapter 8. SIP Services
Delete Row
If you select this box, the row is deleted when you click on Add new rows, Save, or Look up all IP addresses
again.
Create
Enter the number of new rows you want to add to the table, and then click on Create.
Preserve username
When registering a SIP client on one side of the Telecommuting Module to a SIP server on the other side, the
Contact header is normally rewritten. By doing this, we make it possible for the SIP server to track when the same
user is registering multiple times from different places. It is possible to turn this rewriting off and preserve the
username in Contact headers passing through the Telecommuting Module, but that makes it impossible for the SIP
server to tell if registrations for a certain user belong to one or several clients (if a user has two registrations from
different clients and deregisters one of them, the SIP server will delete its only registration for him).
To make all calls work, you need to turn this On.
Select if usernames should be preserved or not. The recommended setting is to Preserve username in Contact
header.
Loose username check
Normally, the Telecommuting Module checks that the authentication username equals the username in the From
header. Some clients use their whole address as authentication username (ie: user@host.com), which means that the
username "user" in the From header is compared with the authentication username "user@host.com". This
authentication will fail. With this function, "@host.com" is stripped from the authentication username.
Select if usernames should be checked loosely (Yes) or strictly (No).
SIP URL encryption
In some situations some SIP URLs are encrypted and signed. When an invitation to a call is sent out, the address
that the callee is to send its answer to is encrypted, if the outgoing packet is NAT:ed. When the answer from the
callee comes in, the Telecommuting Module checks that the encryption and signing is correct before the address is
used to send the information onwards.
The encryption and signing makes the SIP packets slightly larger. This might lead to SIP packets being fragmented.
By turning encryption off, fragmentation can be avoided in some cases, and since some equipment has trouble with
fragmented packets this can sometimes be necessary.
Please note that when encryption is turned off, the Telecommuting Module maked no checks of incoming SIP
URLs. It becomes possible in theory to trick the Telecommuting Module to send SIP packets anywhere, which
means that security is drastically reduced if encryption is turned off.
If Remote NAT Traversal is used, the URL encryption must be turned on.
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