Hi Daniel.
We are using now kamailio 4.4.6
"the latest release series should have a safety check.." does it mean stable 5.0.4 ?
Well it is a reasonable advice I think, we haven't tried this way, yet.

I thought about using uac + dialog module together, but this entails a lot of changes in common logic.

For that moment looks like disabling the restore_mode and restore_dlg parameters solved the problem.
So that, it is enough for me to keep calm. But further, I want to make an effort to turn on dialog/uac modules together.

Thanks for your answers.
I will continue this topic as soon as I will start to work with it.

>Hello,
>
>it would be useful to know also the version of kamailio that is run
>there. The latest release series should have a safety check in order to
>prevent setting an invalid restored From/To URI.
>
>On the other hand, if the UA doesn't preserve the From/To, then it
>doesn't require to be unchanged, so the update (without auto restore) of
>the From/To can be done only for initial INVITE, when UA takes the
>caller/callee ids. For requests within the dialog, these headers can be
>left unchanged or changed to something like anonymous at anonymous.invalid
>
>The last option here, which is the safest, is to use dialog module
>together with uac, so uac module stores the From/To values inside the
>dialog and restores them from there, instead of relying on
>record-routing and the masking algorithm for values.
>
>Cheers,
>Daniel
>
>
>>On 14.11.17 08:04, Julia Boudniatsky wrote:
>> Hello,
>>
>> It looks like headers "From" in initial INVITE and received message
>> are different.
>>
>> For example:
>>  in INVITE : <sip:useragent7122 at kamailio_address:5068>>
>>  in received message : <sip:useragent7122 at kamailio_address>>
>>
>> When you use header "From" transformation (I see Route with vsf),
>> restore may be correct only for exactly the same header "From".
>> Check may be port number is missing/added in  received message header
>> "From".
>>
>> Best regards,
>> Julia
>>
>> On Mon, Nov 13, 2017 at 5:05 PM, Donat Zenichev
>> <donat.zenichev at gmail.com <mailto:donat.zenichev at gmail.com>>>> wrote:
>>
>>     Hi community.
>>     We experience the problem with malformed messages.
>>
>>     First of all, I want to say, that most of time kamailio works well
>>     and nothing happens that can drop sessions.
>>     But from time-to-time something changes (may be in the network)
>>     and kamailio receives requests with malformed headers (To or From
>>     hfs).
>>
>>     The schema:
>>     uplinks ->> kamailio <->> routing server (asterisk)
>>
>>     Malformed messages were received only from asterisk server.
>>     Sip debug on asterisk showed that messages were transmitted
>>     correctly and headers were nice.
>>     But kamailio obtains changed (broken) packets or perhaps can't
>>     read them properly.
>>
>>     How does it look like:
>>     Nov 10 12:37:06 kamailio-name kamailio[965]: INFO: <script>>: Going
>>     to NATMANAGE for BYE from sip:useragent7122 at kamailio_address:5068
>>     (IP=wss:client_address:62881) -
>>     R=sip:dialed_did_service at asterisk_address:50600
>>     ID=1b0044070de406153bf0e4b84d6bb793 at asterisk_address:50600
>>     Nov 10 12:37:06 kamailio-name kamailio[965]: NOTICE: <script>>:
>>     Relaying request to <null>> -
>>     R=sip:dialed_did_service at asterisk_address:50600
>>     ID=1b0044070de406153bf0e4b84d6bb793 at asterisk_address:50600
>>     Nov 10 12:37:06 kamailio-name kamailio[965]: ERROR: <core>>
>>     [parser/parse_addr_spec.c:719]: parse_addr_spec(): unexpected char
>>     [<] in status 6: [<sip:useragent6] .
>>     Nov 10 12:37:06 kamailio-name kamailio[965]: ERROR: <core>>
>>     [parser/parse_from.c:75]: parse_from_header(): bad From header
>>     [<sip:useragent6<+.w>>;tag=jja7l45gd1]
>>     Nov 10 12:37:06 kamailio-name kamailio[965]: ERROR: dialog
>>     [dlg_cseq.c:89]: dlg_cseq_prepare_msg(): cannot parse FROM header
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: <core>>
>>     [parser/parse_addr_spec.c:719]: parse_addr_spec(): unexpected char
>>     [<] in status 6: [<sip:useragent6] .
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: <core>>
>>     [parser/parse_from.c:75]: parse_from_header(): bad From header
>>     [<sip:useragent6<+.w>>;tag=jja7l45gd1]
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: dialog
>>     [dlg_cseq.c:89]: dlg_cseq_prepare_msg(): cannot parse FROM header
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: <core>>
>>     [parser/parse_addr_spec.c:719]: parse_addr_spec(): unexpected char
>>     [<] in status 6: [<sip:useragent6] .
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: <core>>
>>     [parser/parse_from.c:75]: parse_from_header(): bad From header
>>     [<sip:useragent6<+.w>>;tag=jja7l45gd1]
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: uac
>>     [replace.c:783]: restore_uris_reply(): failed to find/parse FROM hdr
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: <core>>
>>     [parser/parse_addr_spec.c:719]: parse_addr_spec(): unexpected char
>>     [<] in status 6: [<sip:useragent6] .
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: <core>>
>>     [parser/parse_from.c:75]: parse_from_header(): bad From header
>>     [<sip:useragent6<+.w>>;tag=jja7l45gd1]
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: pv
>>     [pv_core.c:465]: pv_get_from_attr(): cannot parse From header
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: INFO: <script>>: Skip
>>     manage DEVICE_STATE for BYE from <null>>
>>     (IP=udp:asterisk_address:50600) with (200 - OK) - R=<null>>
>>     ID=1b0044070de406153bf0e4b84d6bb793 at asterisk_address:50600
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: INFO: <script>>:
>>     ------------------------------------MANAGE BYE by
>>     DEVICE_STATE_BYE_MANAGE route - 200 - OK M=BYE
>>     IP=udp:asterisk_address:50600
>>     ID=1b0044070de406153bf0e4b84d6bb793 at asterisk_address:50600
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: <core>>
>>     [parser/parse_addr_spec.c:719]: parse_addr_spec(): unexpected char
>>     [<] in status 6: [<sip:useragent6] .
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: <core>>
>>     [parser/parse_from.c:75]: parse_from_header(): bad From header
>>     [<sip:useragent6<+.w>>;tag=jja7l45gd1]
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: pv
>>     [pv_core.c:465]: pv_get_from_attr(): cannot parse From header
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: <core>>
>>     [parser/parse_addr_spec.c:719]: parse_addr_spec(): unexpected char
>>     [<] in status 6: [<sip:useragent6] .
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: <core>>
>>     [parser/parse_from.c:75]: parse_from_header(): bad From header
>>     [<sip:useragent6<+.w>>;tag=jja7l45gd1]
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: rtpengine
>>     [rtpengine_funcs.c:331]: get_from_tag(): failed to parse From header
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: rtpengine
>>     [rtpengine.c:2252]: rtpp_function_call(): can't get From tag
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: <core>>
>>     [parser/parse_addr_spec.c:719]: parse_addr_spec(): unexpected char
>>     [<] in status 6: [<sip:useragent6] .
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: <core>>
>>     [parser/parse_from.c:75]: parse_from_header(): bad From header
>>     [<sip:useragent6<+.w>>;tag=jja7l45gd1]
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: pv
>>     [pv_core.c:465]: pv_get_from_attr(): cannot parse From header
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: <core>>
>>     [parser/parse_addr_spec.c:719]: parse_addr_spec(): unexpected char
>>     [<] in status 6: [<sip:useragent6] .
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: <core>>
>>     [parser/parse_from.c:75]: parse_from_header(): bad From header
>>     [<sip:useragent6<+.w>>;tag=jja7l45gd1]
>>     Nov 10 12:37:06 kamailio-name kamailio[937]: ERROR: pv
>>     [pv_core.c:465]: pv_get_from_attr(): cannot parse From header
>>
>>     How the packet looks like:
>>     ACK
>>     sip:tt7etmau at bb0pd5t63b26.invalid;alias=client_address~57573~6;transport=ws
>>     SIP/2.0
>>     Via: SIP/2.0/UDP asterisk_address:50600;branch=z9hG4bK117106ca;rport
>>     Route:
>>     <sip:kam2.domain.com:5068;nat=yes;transport=udp;r2=on;ftag=as06869a5d;lr=on;vsf=AAAAAEZZSVVDVV1VRBlUUkUpFQxdVUZYXiRCHU1RQl1HRVNaXhhAQ3RuLnR3aWxpby5jb20-;vst=AAAAAAAAAAAAAAAAAAAAAAAfBwQRQE8NBR9BChIFAwddCgADFEVDQlYudHdpbGlvLmNvbQ--;did=b0c.7331>>,<sip:kam2.callision.com:5068
>>     <http://kam2.callision.com:5068>>;nat=yes;transport=ws;r2=on;ftag=as06869a5d;lr=on;vsf=AAAAAEZZSVVDVV1VRBlUUkUpFQxdVUZYXiRCHU1RQl1HRVNaXhhAQ3RuLnR3aWxpby5jb20-;vst=AAAAAAAAAAAAAAAAAAAAAAAfBwQRQE8NBR9BChIFAwddCgADFEVDQlYudHdpbGlvLmNvbQ--;did=b0c.7331>>
>>     Max-Forwards: 70
>>     From: "19172423539 <tel:%28917%29%20242-3539>>" <sip:19172423539
>>     <tel:%28917%29%20242-3539>>@asterisk_address:50600>>;tag=as06869a5d
>>     To: <sip:useragent7122 at 10.0.1.18:5068
>>     <http://sip:useragent7122@10.0.1.18:5068>>>>;tag=nmv7kmpau3
>>     Contact: <sip:19172423539
>>     <tel:%28917%29%20242-3539>>@asterisk_address:50600>>
>>     Call-ID: 629d5a132c194c536b5f5c1a2a3c6e32 at asterisk_address:50600
>>     CSeq: 102 ACK
>>     User-Agent: asterisk PBX
>>     Content-Length: 0
>>
>>
>>     The transport is used to send messages between asterisk and
>>     kamailio is TCP.
>>     TCP configurations:
>>     tcp_connection_lifetime=3604
>>     tcp_accept_no_cl=yes
>>     tcp_connect_timeout=5
>>     tcp_send_timeout=5
>>     tcp_rd_buf_size=16384
>>     tcp_keepalive=yes
>>     tcp_crlf_ping=yes
>>     tcp_keepcnt=3
>>     tcp_keepidle=30
>>     tcp_keepintvl=15
>>     tcp_max_connections=4096 
>>
>>     I found the idea, that we need to change following parameters:
>>     modparam("uac","restore_mode","auto")
>>     modparam("uac","restore_dlg",1)
>>
>>     to:
>>     modparam("uac","restore_mode","none")
>>     modparam("uac","restore_dlg",0)
>>
>>     I did that, now it looks like all is fine, but I think it can get
>>     back.
>>     Thanks in advance.
>>
>>
>>
>>     -- 
>>     -- 
>>     BR, Donat Zenichev
>>     Wnet VoIP team
>>     Tel Ukraine:  +380(44) 5-900-800
>>     Tel USA: +164(67) 8-174-17
>>     https://w-net.us/ <http://wnet.ua>>
>>
>>     _______________________________________________
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>>
>>
>>
>>
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>>-- 
>Daniel-Constantin Mierla
>www.twitter.com/miconda -- www.linkedin.com/in/miconda
>Kamailio Advanced Training, Nov 13-15, 2017, in Berlin - www.asipto.com
>Kamailio World Conference - www.kamailioworld.com