Forum Discussion
avi_krivorot_73
Nimbostratus
NimbostratusModifying SIP VIA header
Hi,
When we get a SIP INVITE from someone, the F5 always appends something to the reply message (TRYING) in the VIA header, see example:
Original INVITE:
Via: SIP/2.0/UDP 208.71.172.16:5060;branch=z9hG4bK-76ff6f00ffffff10ff000018ff2fff20
Reply TRYING:
Via: SIP/2.0/UDP 208.71.172.16:5060;branch=z9hG4bK-76ff6f00ffffff10ff000018ff2fff20;received=208.71.172.12
I need to strip the extra information ";received=208.71.172.12".
I noticed there is an iRule function for this. Does anyone know how this is done?
Dave_WileyYou could just do a findstr on the UDP::Payload for the "received" text and remove it from the packet.
avi_krivorot_73thanks for the information, although this packet is still part of the sip signaling, not the payload. Can i still use the UDP::Payload?
And if yes, could you point me twards some good documents about this function (or perhaps a small example)? i have not writen any iRules yet, but am a quick learner.
Thanks.
Avi- First of all, string ";received=xxx" was added by the server behind F5 box, NOT Bigip.
Certainly, Bigip can help you remove that string in the response, the basic idea is to find the occurrence in UDP payload and remove it, an example:rule xxx { when SERVER_DATA { if {[regexp -indices {(;received=[0-9.]+)} [UDP::payload] location] == 1} { set offset [lindex $location 0] set len [expr [lindex $location 1] - [lindex $location 0] + 1] UDP::payload replace $offset $len "" } } }
You should be able to find more in iRULE doc - Al_Walter_10251What version of code are you running? Here is what I get if I tried your sample:
01070151:3: Rule [SIP_NAT_iRule] error:
line 1: [unknown event (SIP_RESPONSE)] [when SIP_RESPONSE {
}] - avi_krivorot_73I am running 9.4. I'm not sure if your version supports this.
But what i had to do to get SIP working was configure SIP Persistance under Profiles. Just create one with SIP as the type.
Then you need to assign this to your virtual server. Once i did this, all started to work well.
