$re = '/\bsrc=1.1.1[4-5]{0,1}.[0-9]{0,3}\b.*?\bdeviceOutboundInterface=DOI-Out\b/';
$str = 'Jul 21 11:59:57 Firewall-Name-Removed CEF:0|Fortinet|FortiGate-<removed>|1.2.3,build1111 (GA)|0000000013|forward traffic accept|5|start=Jul 21 2022 11:59:57 logver=604091966 deviceExternalId=FG9H5A3J1789999 dvchost=Firewall-Name-Removed ad.vd=root ad.eventtime=1111111111111111111 ad.tz=-9999 ad.logid=0000000013 cat=traffic ad.subtype=forward deviceSeverity=notice src=1.1.1.1 shost=RandomHost1 spt=62119 deviceInboundInterface=DII-Out ad.srcintfrole=lan ad.srcssid=SSID Has Been Removed ad.apsn=ABC123D ad.ap=CHL-07 ad.channel=157 ad.radioband=802.11ac n-only ad.signal=-40 ad.snr=55 dst=2.2.2.2 dpt=53 deviceOutboundInterface=DOI-Out ad.dstintfrole=undefined ad.srccountry=Reserved ad.dstcountry=CountryRemoved externalID=123456789 proto=00 act=accept ad.policyid=000 ad.policytype=policy ad.poluuid=UUID-Removed ad.policyname=policy_name_removed app=DNS ad.trandisp=noop ad.appid=16195 ad.app=DNS ad.appcat=Network.Service ad.apprisk=elevated ad.applist=UTM Name - Removed ad.duration=180 out=0 in=205 ad.sentpkt=0 ad.rcvdpkt=1 ad.utmaction=allow ad.countdns=1 ad.osname=Windows ad.srcswversion=10 ad.mastersrcmac=<MAC removed> ad.srcmac=<MAC removed> ad.srcserver=0 tz="-9999"';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php