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### Description Kamailio 5.2.6 not able to parse uri with host part having underscore '_'. This was working in 5.1 <!-- Explain what you did, what you expected to happen, and what actually happened. --> Migrated from 5.1 to 5.2.6 and started observing uri parse issue ### Troubleshooting

#### Reproduction

<!-- If the issue can be reproduced, describe how it can be done. -->

#### Debugging Data

<!-- If you got a core dump, use gdb to extract troubleshooting data - full backtrace, local variables and the list of the code at the issue location.

gdb /path/to/kamailio /path/to/corefile bt full info locals list

If you are familiar with gdb, feel free to attach more of what you consider to be relevant. -->

``` (paste your debugging data here) ```

#### Log Messages

<!-- Check the syslog file and if there are relevant log messages printed by Kamailio, add them next, or attach to issue, or provide a link to download them (e.g., to a pastebin site). -->

``` (paste your log messages here) ``` Jan 25 08:02:51 ip-10-130-74-93 /usr/local/sbin/kamailio[4055]: DEBUG: <core> [core/pvapi.c:371]: pv_cache_add(): pvar [$avp(gw)] added in cache Jan 25 08:02:51 ip-10-130-74-93 /usr/local/sbin/kamailio[4055]: DEBUG: app_lua [app_lua_sr.c:934]: lua_sr_pv_get_val(): pv get: $(avp(gw){uri.host}) Jan 25 08:02:51 ip-10-130-74-93 /usr/local/sbin/kamailio[4055]: DEBUG: <core> [core/usr_avp.c:887]: parse_avp_ident(): Parsing 'gw' Jan 25 08:02:51 ip-10-130-74-93 /usr/local/sbin/kamailio[4055]: DEBUG: <core> [core/pvapi.c:371]: pv_cache_add(): pvar [$(avp(gw){uri.host})] added in cache Jan 25 08:02:51 ip-10-130-74-93 /usr/local/sbin/kamailio[4055]: DEBUG: <core> [core/parser/parse_uri.c:1264]: parse_uri(): bad host in uri (error at char _ in state 5) parsed: sip:+123456@long(16) /sip:+123456@long_duration.sample.com;timeout=60;carrierid=1212 (62) Jan 25 08:02:51 ip-10-130-74-93 /usr/local/sbin/kamailio[4055]: ERROR: pv [pv_trans.c:1276]: tr_eval_uri(): invalid uri [sip:+123456@long_duration.sample.com;timeout=60;carrierid=1212] Jan 25 08:02:51 ip-10-130-74-93 /usr/local/sbin/kamailio[4055]: ERROR: app_lua [app_lua_sr.c:947]: lua_sr_pv_get_val(): unable to get pv value for [$(avp(gw){uri.host})] Jan 25 08:02:51 ip-10-130-74-93 /usr/local/sbin/kamailio[4055]: DEBUG: app_lua [app_lua_sr.c:1651]: sr_kemi_lua_exec_func_ex(): param[0] for: is_pure_ip is str: #### SIP Traffic

<!-- If the issue is exposed by processing specific SIP messages, grab them with ngrep or save in a pcap file, then add them next, or attach to issue, or provide a link to download them (e.g., to a pastebin site). -->

``` (paste your sip traffic here) ```

### Possible Solutions

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### Additional Information

* **Kamailio Version** - output of `kamailio -v`

``` (paste your output here) ```

* **Operating System**:

<!-- Details about the operating system, the type: Linux (e.g.,: Debian 8.4, Ubuntu 16.04, CentOS 7.1, ...), MacOS, xBSD, Solaris, ...; Kernel details (output of `uname -a`) -->

``` (paste your output here) ```