Chapter8. SIP Services
Delete Row
Ifyou select this box, the row is deleted when you click on Add new rows,Save, or Look up all IP addresses
again.
Create
Enterthe number of new rows you want to add to the table, and then click on Create.
Preserve username
Whenregistering a SIP client on one side of the Telecommuting Module to a SIP server on the other side, the
Contactheader is normally rewritten. By doing this, we make it possible for the SIP server to track when the same
useris registering multiple times from different places. It is possible to turn this rewriting off and preserve the
usernamein Contact headers passing through the Telecommuting Module, but that makes it impossible for the SIP
serverto tell if registrations for a certain user belong to one or several clients (if a user has two registrations from
differentclients and deregisters one of them, the SIP server will delete its only registration for him).
Tomake all calls work, you need to turn this On.
Selectif 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
authenticationwill fail. With this function, "@host.com" is stripped from the authentication username.
Selectif usernames should be checked loosely (Yes) or strictly (No).
SIP URL encryption
Insome situations some SIP URLs are encrypted and signed. When an invitation to a call is sent out, the address
thatthe callee is to send its answer to is encrypted, if the outgoing packet is NAT:ed. When the answer from the
calleecomes in, the Telecommuting Module checks that the encryption and signing is correct before the address is
usedto send the information onwards.
Theencryption and signing makes the SIP packets slightly larger. This might lead to SIP packets being fragmented.
Byturning encryption off, fragmentation can be avoided in some cases, and since some equipment has trouble with
fragmentedpackets this can sometimes be necessary.
Pleasenote 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
meansthat security is drastically reduced if encryption is turned off.
IfRemote NAT Traversal is used, the URL encryption must be turned on.
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